@article {1871, title = {Decoupling build orientation-induced geometric and texture effects on the mechanical response of additively manufactured IN625 thin-walled elements}, journal = {Materials Science and Engineering: A}, volume = {870}, year = {2023}, month = {02}, pages = {144826}, doi = {10.1016/j.msea.2023.144826}, author = {Banerjee, Arunima and Rossin, Jeff and He, Mo-Rigen and Musinski, William and Shade, Paul and Cox, Marie and Schwalbach, Edwin and Pollock, Tresa and Hemker, K.} } @article {1866, title = {Dislocation cells in additively manufactured metallic alloys characterized by electron backscatter diffraction pattern sharpness}, journal = {Materials Characterization}, volume = {197}, year = {2023}, month = {03}, pages = {112673}, doi = {10.1016/j.matchar.2023.112673}, author = {Wang, Fulin and Stinville, Jean-Charles and Charpagne, Marie-agathe and Echlin, Mclean and Agnew, Sean and Pollock, Tresa and Graef, Marc and Gianola, Daniel} } @article {1856, title = {Foreword: {\textquotedblleft}Eurosuperalloys 2022{\textquotedblright}}, journal = {Metallurgical and Materials Transactions A}, volume = {54}, year = {2023}, month = {03}, doi = {10.1007/s11661-023-07021-z}, author = {Cormier, Jonathan and Pollock, Tresa} } @article {1841, title = {Insights into Plastic Localization by Crystallographic Slip from Emerging Experimental and Numerical Approaches}, journal = {Annual Review of Materials Research}, volume = {53}, year = {2023}, month = {07}, pages = {275-317}, doi = {10.1146/annurev-matsci-080921-102621}, author = {Stinville, Jean-Charles and Charpagne, Marie-agathe and Maa{\ss}, Robert and Proudhon, Henry and Ludwig, W. and Callahan, P.G. and Wang, Fulin and Beyerlein, I.J. and Echlin, M.P. and Pollock, T.m.} } @article {1881, title = {Morphological Stability of Solid-Liquid Interfaces Under Additive Manufacturing Conditions}, journal = {Acta Materialia}, volume = {250}, year = {2023}, month = {03}, pages = {118858}, doi = {10.1016/j.actamat.2023.118858}, author = {Tourret, Damien and Klemm-Toole, Jonah and Eres-Castellanos, Adriana and Rodgers, Brian and Becker, Gus and Saville, Alec and Ellyson, Ben and Johnson, Chloe and Milligan, Brian and Copley, John and Ochoa, Ruben and Polonsky, Andrew and Pusch, Kira and Haines, Michael and Fezzaa, Kamel and Sun, Tao and Clarke, Kester and Babu, Suresh and Pollock, Tresa and Clarke, Amy} } @article {1831, title = {Perspective: Large Language Models in Applied Mechanics}, journal = {Journal of Applied Mechanics}, volume = {90}, year = {2023}, month = {06}, pages = {1-12}, doi = {10.1115/1.4062773}, author = {Brodnik, Neal and Carton, Samuel and Muir, Caelin and Ghosh, Satanu and Downey, Doug and Echlin, Mclean and Pollock, Tresa and Daly, Samantha} } @article {1896, title = {Slip localization behavior at triple junctions in nickel-base superalloys}, journal = {Acta Materialia}, volume = {249}, year = {2023}, month = {02}, pages = {118801}, doi = {10.1016/j.actamat.2023.118801}, author = {Hestroffer, Jonathan and Stinville, Jean-Charles and Charpagne, Marie-agathe and Miller, Matthew and Pollock, Tresa and Beyerlein, Irene} } @article {1946, title = {Damage Nucleation During Transverse Creep of a Directionally Solidified Ni-based Superalloy}, journal = {Materials Science and Engineering A}, volume = {858}, year = {2022}, month = {09}, pages = {144089}, doi = {10.1016/j.msea.2022.144089}, author = {Cormier, Jonathan and Stinville, Jean-Charles and Mataveli Suave, Lorena and Mauget, Florent and Patrick, Villechaise and Marcin, Lionel and Pollock, Tresa} } @article {2026, title = {Development of grain-scale slip activity and lattice rotation fields in Inconel 718}, journal = {Acta Materialia}, volume = {226}, year = {2022}, month = {01}, pages = {117627}, doi = {10.1016/j.actamat.2022.117627}, author = {Hestroffer, Jonathan and Latypov, Marat and Stinville, Jean-Charles and Charpagne, Marie-agathe and Valle, Valery and Miller, Matthew and Pollock, Tresa and Beyerlein, Irene} } @article {2021, title = {Experimental investigation and thermodynamic modelling of the Mg{\textendash}Al-rich region of the Mg{\textendash}Al{\textendash}Sr System}, journal = {International Journal of Materials Research}, volume = {97}, year = {2022}, month = {01}, pages = {422-428}, doi = {10.1515/ijmr-2006-0070}, author = {Cao, Hongbo and Zhu, Jun and Zhang, Chuan and Wu, Kaisheng and Saddock, Nicholas and Jones, J. and Pollock, Tresa and Schmid-Fetzer, Rainer and Chang, Y.} } @article {1956, title = {Heterogeneous slip localization in an additively manufactured 316L stainless steel}, journal = {International Journal of Plasticity}, volume = {159}, year = {2022}, month = {09}, pages = {103436}, doi = {10.1016/j.ijplas.2022.103436}, author = {Bean, Christopher and Wang, Fulin and Charpagne, Marie-agathe and Villechaise, P. and Valle, Valery and Agnew, S.R. and Gianola, D.S. and Pollock, T.m. and Stinville, Jean-Charles} } @article {1981, title = {In Situ X-ray Radiography and Computational Modeling to Predict Grain Morphology in β-Titanium during Simulated Additive Manufacturing}, journal = {Metals}, volume = {12}, year = {2022}, month = {07}, pages = {1217}, doi = {10.3390/met12071217}, author = {Jasien, Chris and Saville, Alec and Becker, Chandler and Klemm-Toole, Jonah and Fezzaa, Kamel and Sun, Tao and Pollock, Tresa and Clarke, Amy} } @article {1931, title = {Materials for extreme environments}, journal = {Nature Reviews Materials}, volume = {8}, year = {2022}, month = {11}, doi = {10.1038/s41578-022-00496-z}, author = {Eswarappa Prameela, Suhas and Pollock, Tresa and Raabe, Dierk and Meyers, Marc and Aitkaliyeva, Assel and Chintersingh, Kerri-Lee and Cordero, Zachary and Graham-Brady, Lori} } @article {1996, title = {Microstructure Evolution and Tensile Properties of a Selectively Laser Melted CoNi-Base Superalloy}, journal = {Metallurgical and Materials Transactions A}, volume = {53}, year = {2022}, month = {05}, doi = {10.1007/s11661-022-06716-z}, author = {Murray, Sean and Raeker, Evan and Pusch, Kira and Frey, Carolina and Torbet, Chris and Zhou, Ning and Forsik, St{\'e}phane and Dicus, Austin and Colombo, Gian and Kirka, M. and Pollock, Tresa} } @article {1966, title = {Multi-modal Dataset of a Polycrystalline Metallic Material: 3D Microstructure and Deformation Fields}, journal = {Scientific Data}, volume = {9}, year = {2022}, month = {08}, doi = {10.1038/s41597-022-01525-w}, author = {Stinville, Jean-Charles and Hestroffer, Jonathan and Charpagne, Marie-agathe and Polonsky, Andrew and Echlin, M. and Torbet, Chris and Valle, Valery and Nygren, K. and Miller, M. and Klaas, Ottmar and Loghin, Adrian and Beyerlein, I. and Pollock, T.} } @article {2006, title = {Observation of bulk plasticity in a polycrystalline titanium alloy by diffraction contrast tomography and topotomography}, journal = {Materials Characterization}, volume = {188}, year = {2022}, month = {04}, pages = {111891}, doi = {10.1016/j.matchar.2022.111891}, author = {Stinville, Jean-Charles and Ludwig, Wolfgang and Callahan, P.G. and Echlin, M.P. and Valle, Valery and Pollock, T.m. and Proudhon, Henry} } @article {2001, title = {Orientation dependent plastic localization in the refractory high entropy alloy HfNbTaTiZr at room temperature}, journal = {Materials Science and Engineering: A}, volume = {848}, year = {2022}, month = {05}, pages = {143291}, doi = {10.1016/j.msea.2022.143291}, author = {Charpagne, Marie-agathe and Stinville, Jean-Charles and Wang, Fulin and Philips, Noah and Pollock, T.m.} } @article {1951, title = {On the origins of fatigue strength in crystalline metallic materials}, journal = {Science}, volume = {377}, year = {2022}, month = {09}, pages = {1065-1071}, doi = {10.1126/science.abn0392}, author = {Stinville, Jean-Charles and Charpagne, Marie-agathe and Cervellon, Alice and H{\'e}mery, Samuel and Wang, Fulin and Callahan, P. and Valle, Valery and Pollock, T.} } @article {1811, title = {Single crystal elastic constants of additively manufactured components determined by resonant ultrasound spectroscopy}, journal = {Materials Characterization}, volume = {192}, year = {2022}, pages = {112244}, abstract = {

Bayesian inference with Sequential Monte Carlo was used to determine the single crystal elastic constants of additively manufactured (AM) cobalt-nickel-based superalloy specimens from only the resonant frequencies and texture data. This novel framework enables the quantification of the single crystal elastic constants for AM and polycrystalline specimens using only electron backscatter diffraction (EBSD) and Resonant Ultrasound Spectroscopy (RUS), avoiding the expense of bulk single crystal fabrication or synchrotron experiments. A parallelizable and open-source Python package (SMCPy) was used to perform Bayesian inference of the single crystal elastic constants from resonant frequencies of AM specimens. The single crystal elastic constants determined from AM cobalt-nickel-base superalloy specimens were validated with measurements of the single crystal elastic constants on a bulk single crystal specimen. EBSD texture data was used to determine the single crystal elastic constants from the resonant frequencies of AM specimens, and validated with neutron diffraction data by considering the experimental uncertainty in both the EBSD and neutron diffraction data. The robustness of this framework for varied texture orientations relative to the build direction (BD) was demonstrated for AM specimens printed at 0\° and 20\° BD-inclinations.

}, issn = {1044-5803}, doi = {https://doi.org/10.1016/j.matchar.2022.112244}, url = {https://www.sciencedirect.com/science/article/pii/S1044580322005265}, author = {Jeff Rossin and Patrick Leser and Kira Pusch and Carolina Frey and Sven C. Vogel and Alec I. Saville and Chris Torbet and Amy J. Clarke and Samantha Daly and Tresa M. Pollock} } @article {1936, title = {Subgrain geometrically necessary dislocation density mapping in spalled Ta in three dimensions}, journal = {Acta Materialia}, volume = {244}, year = {2022}, month = {11}, pages = {118366}, doi = {10.1016/j.actamat.2022.118366}, author = {Witzen, Wyatt and Echlin, Mclean and Charpagne, Marie-agathe and Pollock, Tresa and Beyerlein, Irene} } @article {2081, title = {Crack initiation anisotropy of Ni-based SX superalloys in the very high cycle fatigue regime}, journal = {Materials Science and Engineering: A}, volume = {825}, year = {2021}, month = {08}, pages = {141920}, doi = {10.1016/j.msea.2021.141920}, author = {Cervellon, Alice and Torbet, Chris and Pollock, Tresa} } @article {1681, title = {Damage mechanisms during very high cycle fatigue of a coated and grit-blasted Ni-based single-crystal superalloy}, journal = {International Journal of Fatigue}, volume = {142}, year = {2021}, abstract = {

The very high cycle fatigue properties of the Ni-based single-crystal superalloy CMSX-4 coated with an MCrAlY type coating and grit-blasted were studied at 1000 \°C, 20 kHz and R = -1. A recrystallized layer thicker than the size of the larger casting pores (\>50 \μm) drastically reduces the fatigue life without environmental influence. The recrystallized layer and roughness introduced by grit-blasting degrades the environmental resistance of the alloy and the resultant fatigue life. The fatigue life of the coated specimens is also greatly reduced from damage accumulation in the interdiffusion zone by grain boundary cracking, oxidation and internal nitridation.

}, keywords = {Coating, Oxidation, Recrystallization, Single-crystal superalloy, Very high cycle fatigue}, issn = {01421123}, doi = {10.1016/j.ijfatigue.2020.105962}, author = {Cervellon, Alice and Bortoluci Ormastroni, Luciana Maria and Hervier, Z{\'e}line and Pollock, Tresa M. and Pedraza, Fernando and Cormier, Jonathan} } @article {2096, title = {High-throughput approach for estimation of intrinsic barriers in FCC structures for alloy design}, journal = {Scripta Materialia}, volume = {204}, year = {2021}, month = {07}, pages = {114126}, doi = {10.1016/j.scriptamat.2021.114126}, author = {Vamsi, K V and Charpagne, Marie-agathe and Pollock, Tresa} } @article {2156, title = {On the Localization of Plastic Strain in Microtextured Regions of Ti-6Al-4V}, journal = {Acta Materialia}, volume = {204}, year = {2021}, month = {02}, pages = {116492}, doi = {10.1016/j.actamat.2020.116492}, author = {Cappola, Jonathan and Stinville, Jean-Charles and Charpagne, Marie-agathe and Callahan, Patrick and Echlin, Mclean and Pollock, Tresa and Pilchak, Adam and Kasemer, Matthew} } @article {2056, title = {Low cycle fatigue of a single crystal CoNi-base superalloy}, journal = {Materials Science and Engineering A}, volume = {827}, year = {2021}, month = {09}, doi = {10.1016/j.msea.2021.142007}, author = {Murray, Sean and Cervellon, Alice and Cormier, Jonathan and Pollock, Tresa} } @article {2146, title = {Mechanical Metrics of Virtual Polycrystals (MechMet)}, journal = {Integrating Materials and Manufacturing Innovation}, volume = {10}, year = {2021}, month = {04}, pages = {1-21}, doi = {10.1007/s40192-021-00206-7}, author = {Dawson, Paul and Miller, Matthew and Pollock, Tresa and Wendorf, Joe and Mills, Leah and Stinville, Jean-Charles and Charpagne, Marie-agathe and Echlin, Mclean} } @article {2141, title = {Microstructure-Based Estimation of Strength and Ductility Distributions for α+β Titanium Alloys}, journal = {Metallurgical and Materials Transactions A}, year = {2021}, month = {04}, doi = {10.1007/s11661-021-06233-5}, author = {Echlin, Mclean and Kasemer, Matthew and Chatterjee, Kamalika and Boyce, Donald and Stinville, Jean-Charles and Callahan, Patrick and Wielewski, Euan and Park, Jun-Sang and Williams, James and Suter, Robert and Pollock, Tresa and Miller, Matthew and Dawson, Paul} } @article {2131, title = {Multimodal 3D Characterization of Voids in Shock-Loaded Tantalum: Implications for Ductile Spallation Mechanisms}, journal = {Acta Materialia}, volume = {215}, year = {2021}, month = {06}, pages = {117057}, doi = {10.1016/j.actamat.2021.117057}, author = {Francis, Toby and Rottmann, Paul and Polonsky, Andrew and Charpagne, Marie-agathe and Echlin, Mclean and Livescu, Veronica and Jones, David and Gray, G. and Graef, Marc and Pollock, Tresa} } @article {2051, title = {A Multi-modal Data Merging Framework for Correlative Investigation of Strain Localization in Three Dimensions}, journal = {JOM}, volume = {73}, year = {2021}, month = {09}, doi = {10.1007/s11837-021-04894-6}, author = {Charpagne, Marie-agathe and Stinville, Jean-Charles and Polonsky, Andrew and Echlin, M. and Pollock, T.} } @article {2151, title = {Rejuvenation of Directionally Solidified and Single-Crystal Nickel-Base Superalloys}, journal = {Metallurgical and Materials Transactions A}, volume = {52}, year = {2021}, month = {03}, doi = {10.1007/s11661-021-06150-7}, author = {Rettberg, Luke and Callahan, P. and Goodlet, Brent and Pollock, T.} } @article {2106, title = {Slip localization in Inconel 718: A three-dimensional and statistical perspective}, journal = {Acta Materialia}, volume = {215}, year = {2021}, month = {06}, pages = {117037}, doi = {10.1016/j.actamat.2021.117037}, author = {Charpagne, Marie-agathe and Hestroffer, Jonathan and Polonsky, Andrew and Echlin, M.P. and Texier, Damien and Valle, Valery and Beyerlein, I.J. and Pollock, T.m. and Stinville, Jean-Charles} } @article {2071, title = {Strain Localization and Fatigue Crack Formation at ( 0001 ) Twist Boundaries in Titanium Alloys}, journal = {Acta Materialia}, volume = {219}, year = {2021}, month = {08}, pages = {117227}, doi = {10.1016/j.actamat.2021.117227}, author = {H{\'e}mery, Samuel and Stinville, Jean-Charles and Wang, Fulin and Charpagne, Marie-agathe and Emigh, M.G. and Pollock, T.m. and Valle, Valery} } @conference {1596, title = {3D Characterization of the Columnar-to-Equiaxed Transition in Additively Manufactured Inconel 718}, booktitle = {Superalloys 2020}, year = {2020}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, abstract = {

Additive manufacturing (AM) provides enormous process- ing flexibility, enabling novel part geometries and opti- mized designs. Access to a local heat source further per- mits the potential for local microstructure control on the scale of individual melt pools, which can enable local con- trol of part properties. In order to design tailored process- ing strategies for target microstructures, models predict- ing the columnar-to-equiaxed transition must be extended to the high solidification velocities and complex thermal histories present in AM. Here, we combine 3D charac- terization with advanced modeling techniques to develop a more complete understanding of the solidification pro- cess and evolution of microstructure during electron beam melting (EBM) of Inconel 718. Full calibration of existing microstructure prediction models demonstrates the differ- ences between AM processes and more conventional weld- ing techniques, underlying the need for accurate deter- mination of key parameters that can only be measured directly in 3D. The ability to combine multisensor data in a consistent 3D framework via data fusion algorithms is essential to fully leverage these advanced characteriza- tion approaches. Thermal modeling provides insight on microstructure development within isolated solidification events and demonstrates the role of Marangoni effects on controlling solidification behavior.

}, keywords = {Additive manufacturing, Microstructure, Solidification, Tomography}, isbn = {9783030518349}, doi = {10.1007/978-3-030-51834-9}, url = {http://dx.doi.org/10.1007/978-3-030-51834-9_65}, author = {Polonsky, Andrew T. and Raghavan, Narendran and Echlin, Mclean P. and Kirka, Michael M. and Dehoff, Ryan R. and Pollock, Tresa M.}, editor = {Tin, Sammy and Hardy, Mark and Clews, Justin and Cormier, Jonathan and Feng, Qiang and Marcin, John and O{\textquoteright}Brien, Chris and Suzuki, Akane} } @article {1806, title = {Assessment of grain structure evolution with resonant ultrasound spectroscopy in additively manufactured nickel alloys}, journal = {Materials Characterization}, volume = {167}, year = {2020}, pages = {110501}, abstract = {

Despite the advantages of metal additive manufacturing (AM), ensuring integrity and reproducibility for built components is a barrier to the implementation of AM components in critical applications. Component qualification necessitates Non-Destructive Evaluation (NDE), but existing NDE frameworks are insufficient for the rapid and cost effective screening of variable AM components. In this study, alterations in laser powder bed fusion (LPBF) AM process parameters were characterized using resonant ultrasound spectroscopy (RUS). Samples that were subjected to a Hot Isostatic Press (HIP) and Heat Treatment (HT) post-processing step exhibited changes in resonance frequencies that varied in magnitude and direction with the type of resonance mode. The initial build direction prior to HIP and HT had a negligible effect on resonant frequency changes after recrystallization. The change in resonant frequencies at each process condition was predicted using Finite Element Modeling (FEM) informed with Electron Backscatter Diffraction (EBSD) data. FEM identified that the experimentally measured change in resonant response between the initially textured state and the recrystallized state was dominated by grain orientation dependent changes in elasticity. The EBSD-estimated elastic constants and FEM results were validated using experimental laser vibrometry and RUS inversion of elastic constants. RUS Inversion by Bayesian inference and Hamiltonian Monte Carlo has not been used to characterize an AM nickel-base alloy prior to this work. These results demonstrate that RUS is capable of detecting part to part microstructure variability between built AM components.

}, keywords = {Additive manufacturing, Bayesian inference, Elastic constant inversion, Finite element modeling, Recrystallization, Resonance ultrasound spectroscopy}, issn = {1044-5803}, doi = {https://doi.org/10.1016/j.matchar.2020.110501}, url = {https://www.sciencedirect.com/science/article/pii/S1044580320319720}, author = {Jeff Rossin and Brent Goodlet and Chris Torbet and William Musinski and Marie Cox and Jonathan Miller and Michael Groeber and Alexander Mayes and Eric Biedermann and Stephen Smith and Samantha Daly and Tresa Pollock} } @article {1416, title = {Automated and quantitative analysis of plastic strain localization via multi-modal data recombination}, journal = {Materials Characterization}, volume = {163}, year = {2020}, pages = {110245}, issn = {10445803}, doi = {10.1016/j.matchar.2020.110245}, url = {https://linkinghub.elsevier.com/retrieve/pii/S1044580319335569}, author = {Charpagne, M.A. and Stinville, J.C. and Callahan, P.G. and Texier, D. and Chen, Z. and Villechaise, P. and Valle, V. and Pollock, T.m.} } @conference {1611, title = {Creep, Fatigue, and Oxidation Interactions During High and Very High Cycle Fatigue at Elevated Temperature of Nickel-Based Single Crystal Superalloys}, booktitle = {Superalloys 2020}, year = {2020}, abstract = {

High-temperature fatigue of Ni-based single crystal superalloys is studied at 1000 \°C in a wide range of loading conditions (\−1 ? R ? 0.8) and number of cycles (103 \− 109). Under fully reversed conditions, a competition between crack initiations from the surface\— assisted by oxidation\—and from internal metallurgical defects\—mostly large casting pores\—is observed. Increasing the testing frequency shifts the competition to a higher number of cycles. Conversely, decreasing the casting pore size or coating the specimen promotes surface initiations. When a positive mean stress is added (R ? 0), a creep deformation/damage mechanism mainly controls fatigue life, despite fracture surfaces presenting a variety of initiation types. Fatigue life can be predicted by a simple creep law if the contribution of the alternating stress is considered. A linear damage summation method that considers pure fatigue and pure creep damage is used to predict the fatigue lives, and Haigh diagrams for different alloys are presented.

}, keywords = {Creep, fatigue, High temperature, Superalloy}, isbn = {9783030518349}, doi = {10.1007/978-3-030-51834-9}, url = {http://dx.doi.org/10.1007/978-3-030-51834-9_65}, author = {Cervellon, A. and Yi, J. Z. and Corpace, F. and Hervier, Z. and Rigney, J. and Wright, P. K. and Torbet, C. J. and Cormier, J. and Jones, J. W. and Pollock, T. M.}, editor = {Tin, Sammy and Hardy, Mark and Clews, Justin and Cormier, Jonathan and Feng, Qiang and Marcin, John and O{\textquoteright}Brien, Chris and Suzuki, Akane} } @article {1701, title = {Design and Tailoring of Alloys for Additive Manufacturing}, journal = {Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science}, volume = {51}, year = {2020}, pages = {6000{\textendash}6019}, abstract = {

Additive manufacturing (AM) promises a major transformation for manufacturing of metallic components for aerospace, medical, nuclear, and energy applications. This perspective paper addresses some of the opportunities for alloy and feedstock design to achieve site-specific and enhanced properties not attainable by conventional manufacturing processes. This paper provides a brief overview of the role of powders, as well as solidification and solid-state phase transformation phenomena typically encountered during fusion-based AM. Three case studies are discussed that leverage the above to arrive at microstructure control. The first case study focuses on approaches to modify the solidification characteristics by in-situ alloying. The second case study focuses on the need for concurrent design of alloys and processing conditions to arrive at the columnar to equiaxed transition during solidification. The third case study focuses on the design of a cobalt alloy for AM, with emphasis on tailoring liquid and solid state phase transformations. The need for comprehensive knowledge of processing conditions during AM, in-situ and ex-situ probing of microstructure development under AM conditions, and post-print processing, characterization, and qualification are articulated for the design of future alloys and component geometries built by AM.

}, issn = {10735623}, doi = {10.1007/s11661-020-06009-3}, url = {https://doi.org/10.1007/s11661-020-06009-3}, author = {Pollock, T. M. and Clarke, A. J. and Babu, S. S.} } @article {1571, title = {Design of Nickel-Cobalt-Ruthenium Multi-Principal Element Alloys}, journal = {Acta Materialia}, year = {2020}, pages = {16013}, keywords = {Alloy design, Density functional theory, High Entropy Alloys, planar fault energies, TRIP, TWIP}, issn = {1359-6454}, doi = {10.1016/j.actamat.2020.05.003}, url = {https://doi.org/10.1016/j.actamat.2020.05.003}, author = {Charpagne, M A and Vamsi, K V and Eggeler, Y M and Murray, S P and Frey, C and Kolli, S K and Pollock, T M} } @article {1411, title = {Direct measurements of slip irreversibility in a nickel-based superalloy using high resolution digital image correlation}, journal = {Acta Materialia}, volume = {186}, year = {2020}, pages = {172{\textendash}189}, abstract = {

Fatigue crack nucleation in crystalline materials typically develops due to highly localized cyclic slip. During a fatigue cycle, reverse slip differs locally from slip in the forward direction particularly in precipitate-containing materials such as superalloys. In this paper we report the first direct measurements of irreversibility at the scale of individual slip bands by high-resolution digital image correlation (DIC) in a polycrystalline nickel-based superalloy. Quantitative measurements of the slip irreversibility are challenging for regions of material that have a size that captures the microstructure and its variability. High spatial resolution at the nanometer scale during experimental measurements is needed to observe slip localization during deformation. Moreover, large fields are also needed to obtain the material response over statistically representative populations of microstructural configurations. Recently, high resolution scanning electron microscope (SEM) digital image correlation (DIC) has been extended for quantitative analysis of discontinuities induced by slip events using the Heaviside-DIC method. This novel method provides quantitative measurements of slip localization at the specimen surface. In this paper, the Heaviside-DIC method is used to measure slip irreversibility and plastic strain accumulation in a nickel-based superalloy. The method detects bands with high levels of irreversibility early in cycling that ultimately form fatigue cracks upon further cycling. The local microstructural configurations that induce large amounts of plasticity and slip irreversibility are correlated to crack nucleation locations.

}, keywords = {Heaviside-digital image correlation, High resolution digital image correlation, Low cycle fatigue, Polycrystalline Ren{\'e} 88DT nickel-based superalloy, Scanning electron microscopy digital image correlation, Slip irreversibility, Strain localization and accumulation}, issn = {13596454}, doi = {10.1016/j.actamat.2019.12.009}, url = {https://doi.org/10.1016/j.actamat.2019.12.009}, author = {Stinville, J. C. and Callahan, P. G. and Charpagne, M. A. and Echlin, M. P. and Valle, V. and Pollock, T. M.} } @article {1696, title = {Grain refinement mechanisms in additively manufactured nano-functionalized aluminum}, journal = {Acta Materialia}, volume = {200}, year = {2020}, pages = {1022{\textendash}1037}, abstract = {

Additive manufacturing (AM) is a new and promising production methodology adept at producing complex geometries, which can be optimized for lower weight and enhanced capabilities. The material properties of these additive components are dictated by the microstructures developed during processing, with a high sensitivity to grain structure and associated anisotropy. With this new processing modality comes the added difficulty of understanding the thermodynamics and kinetic mechanisms that dictate the evolution of microstructure. This research addresses the unique thermal conditions present in AM and the pathways for grain refinement in nanofunctionalized aluminum alloys. The Al-Ta system, in which Al3Ta intermetallic compounds are demonstrated to have substantial grain refining capacity, are the focus of this study. The grain size is shown to be reduced relative to pure aluminum by 1000X when tantalum is added at 1 vol\%. The effectiveness of the Al3Ta intermetallic is dictated by the crystallography and availability of the inoculant phase under AM conditions.

}, keywords = {Additive manufacturing, Crystallography, Grain refinement, Nucleation, Solidification}, issn = {13596454}, doi = {10.1016/j.actamat.2020.09.043}, url = {https://doi.org/10.1016/j.actamat.2020.09.043}, author = {Martin, J. Hunter and Yahata, Brennan and Mayer, Justin and Mone, Robert and Stonkevitch, Ekaterina and Miller, Julie and O{\textquoteright}Masta, Mark R. and Schaedler, Tobias and Hundley, Jacob and Callahan, Patrick and Pollock, Tresa} } @article {1576, title = {Growth accidents induced by primary γ{\textquoteright} precipitates in a polycrystalline nickel-based superalloy}, journal = {Scripta Materialia}, volume = {186}, year = {2020}, pages = {1{\textendash}5}, keywords = {3D EBSD, Annealing twin boundaries, Critical recrystallization, Nickel-base superalloy, Recrystallization}, issn = {1359-6462}, doi = {10.1016/j.scriptamat.2020.05.020}, url = {https://doi.org/10.1016/j.scriptamat.2020.05.020}, author = {Charpagne, M A and Polonsky, A T and Echlin, M P and Jacomet, S and De Jaeger, J and De Graef, M and Bozzolo, N and Pollock, T M} } @article {1631, title = {Growth accidents induced by primary γ' precipitates in a polycrystalline nickel-based superalloy}, journal = {Scripta Materialia}, volume = {186}, year = {2020}, month = {09/2020}, pages = {109-113}, abstract = {

The development of overgrown grains during sub-solvus annealing of a polycrystalline\ \γ\−\γ\′\ nickel-base alloy is investigated, with special emphasis on the primary\ \γ\′ precipitates. Quantitative analysis conducted on a large three-dimensional electron back-scattered diffraction dataset reveals a high fraction of\ \γ\′ precipitates on the annealing twin boundaries in the large grains. When observed in-situ in a scanning electron microscope, the formation of annealing twins is correlated to the crossing of\ \γ\′ precipitates by moving grain boundaries. The role of precipitates in the occurrence of growth accidents is discussed.

}, keywords = {3D EBSD, Annealing twin boundaries, Critical recrystallization, Nickel-base superalloy, Recrystallization}, doi = {https://doi.org/10.1016/j.scriptamat.2020.05.020}, url = {https://www.sciencedirect.com/science/article/abs/pii/S1359646220302979$\#$fig0005}, author = {M.A. Charpagne and A.T. Polonsky and M.P. Echlin and S. Jacomet and J. de Jaeger and M. De Graef and N. Bozzolo and T.M. Pollock} } @article {1341, title = {Low Cycle Fatigue of Single Crystal γ'-containing Co-based Superalloys at 750 {\textdegree}C}, journal = {Metallurgical and Materials Transactions A}, volume = {51}, year = {2020}, pages = {200{\textendash}213}, abstract = {

A new class of \γ\′-containing Co-based superalloys that are promising for high temperature applications has been investigated under cyclic loading conditions. A series of single crystal variants of these Co-based superalloys have been cyclically loaded above their elastic limit at 750 \°C in air to study their behavior in the low cycle regime. Interrupted testing was performed to observe the early stages of fatigue failure. Optical microscopy, scanning electron microscopy, and transmission electron microscopy were used to characterize post-mortem specimens. Fatigue failure occurred due to surface cracks that developed during the early stages of cycling in the aluminide-coated sample gauge sections. Growth of these surface cracks into the substrate was associated with extensive oxidation and intermetallic phase precipitation, which accelerated crack propagation as compared to Ni-based superalloys. These observations suggest that improvements in the oxidation resistance and high temperature strength of \γ\′-containing Co-based superalloys will enhance their fatigue behavior.

}, issn = {1543-1940}, doi = {10.1007/s11661-019-05508-2}, url = {https://doi.org/10.1007/s11661-019-05508-2}, author = {Murray, Sean P and Stinville, Jean-Charles and Callahan, Patrick G and Rhein, Robert K and Pollock, Tresa M} } @article {1626, title = {Measurement of elastic and rotation fields during irreversible deformation using Heaviside-digital image correlation}, journal = {Materials Characterization}, volume = {169}, year = {2020}, month = {11/2020}, pages = {110600}, abstract = {

The recent development of the high resolution and discontinuity-tolerant digital image correlation technique enables the extraction of discontinuities within a displacement field. The technique provides quantitative analysis of discontinuities arising from slip, shear bands, cracks, and grain boundary sliding in a variety of material systems, including polycrystalline metallic materials. The discontinuity-tolerant digital image correlation method can be implemented to retrieve not only quantitative discontinuity analysis but also the local strain and rotation fields that operate near these discontinuities. The present implementation includes high-resolution digital image correlation (HR-DIC) measurements collected in a scanning electron microscope for analysis of both the plastic and elastic fields that develop during deformation of polycrystalline metallic materials. The combination of the discontinuity-tolerant DIC technique with the computation of internal gradients enables extraction of non-localized strain and rotation fields during plastic deformation of a nickel-based superalloy. Therefore the lattice rotation/expansion and plastic localization that occur during deformation can be determined in a single experiment. This method is validated using synthetic images with preset deformation, and experimental measurements using the electron back scatter diffraction (EBSD) technique.

}, doi = {https://doi.org/10.1016/j.matchar.2020.110600}, url = {https://www.sciencedirect.com/science/article/abs/pii/S1044580320320714}, author = {J.C. Stinville and M.A. Charpagne and F. Bourdin and P.G. Callahan and Z. Chen and M.P. Echlin and D. Texier and J. Cormier and P. Villechaise and T.M. Pollock and V. Valle} } @conference {1591, title = {Microstructure and Tensile Properties of a CoNi-Based Superalloy Fabricated by Selective Electron Beam Melting}, booktitle = {Superalloys 2020}, year = {2020}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, abstract = {

Successful application of selective electron beam melting to a novel CoNi-based superalloy named SB-CoNi-10 is demonstrated. Crack-free as-printed microstructures exhibit excellent ductilities above 30\% and ultimate tensile strengths above 1.1 GPa at room temperature in tension. Conventional post-processing consisting of a super-solvus hot isostatic pressing (HIP), a solution heat treatment (SHT), and a low-temperature aging has been applied to remove microstructural inhomogeneities present in the as-printed microstructure. The microstructures of the as-printed and HIP+SHT+Aged alloys have been investigated to determine the effect of post-processing heat treatments on the nanoscale \γ/\γ\&$\#$39; microstructure and the mesoscale grain structure. Tensile tests have been conducted at room temperature and elevated temperatures above 850 {\textopenbullet}C to investigate mechanical properties in both the as-printed and HIP+SHT+Aged conditions. The high- temperature ductility and strength are strongly affected by the microstructure, with a mostly columnar-grained microstructure in the as-printed condition exhibiting superior ductility to the fully recrystallized microstructure in the HIP+SHT+Aged condition.

}, keywords = {Additive manufacturing, CoNi-based superalloys, Mechanical properties}, isbn = {9783030518349}, doi = {10.1007/978-3-030-51834-9}, url = {http://dx.doi.org/10.1007/978-3-030-51834-9_65}, author = {Murray, Sean P. and Pusch, Kira M. and Polonsky, Andrew T. and Torbet, Chris J. and Seward, Gareth G. E. and Nandwana, Peeyush and Kirka, Michael M. and Dehoff, Ryan R. and Zhou, Ning and Forsik, St{\'e}phane A. J. and Slye, William and Pollock, Tresa M.}, editor = {Tin, Sammy and Hardy, Mark and Clews, Justin and Cormier, Jonathan and Feng, Qiang and Marcin, John and O{\textquoteright}Brien, Chris and Suzuki, Akane} } @article {1526, title = {Non-destructive evaluation of 3D microstructure evolution in strontium titanate}, journal = {Journal of Applied Crystallography}, volume = {53}, year = {2020}, pages = {1{\textendash}11}, abstract = {

Nondestructive X-ray diffraction contrast tomography imaging was used to characterize the microstructure evolution in a polycrystalline bulk strontium titanate specimen. Simultaneous acquisition of diffraction and absorption information allows for the reconstruction of shape and orientation of more than 800 grains in the specimen as well as porosity. Three-dimensional microstructure reconstructions of two coarsening states of the same specimen are presented alongside a detailed exploration of the crystallographic, topological and morphological characteristics of the evolving microstructure. The overall analysis of the 3D structure shows a clear signature of the grain boundary anisotropy, which can be correlated to surface energy anisotropy: the grain boundary plane distribution function shows an excess of {\textlangle}100{\textrangle}-oriented interfaces with respect to a random structure. The results are discussed in the context of interface property anisotropy effects.

}, keywords = {3d materials, contrast tomography, diffraction, grain growth, microstructure evolution, nondestructive x-ray diffraction contrast, science, strontium titanate, to, tomography imaging was used}, doi = {10.1107/S160057672000093X}, author = {Trenkle, Andreas and Syha, Melanie and Rheinheimer, Wolfgang and Callahan, Patrick and Nhuyen, Lily and Ludwig, Wolfgang and Lenthe, William and Echlin, Mclean and Pollock, Tresa and Weygand, Daniel and Hoffmann, Michael and Gumbsch, Peter} } @conference {1606, title = {Role of Non-metallic Inclusions and Twins on the Variability in Fatigue Life in Alloy 718 Nickel Base Superalloy}, booktitle = {Superalloys 2020}, year = {2020}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, abstract = {

Non-metallic inclusions (NMIs) and slip bands parallel to and slightly offset from twin boundaries are observed to be preferential sites for fatigue crack nucleation in wrought superalloys. Potential interactions between NMI cracking and slip activity within neighboring grains or at twin boundaries were investigated under monotonic tensile loading (up to 1.3\% total strain) at room temper- ature. High resolution- and Heaviside-digital image correlation measurements were performed during inter- rupted tensile loading to identify strain localization, associated slip systems, and damage initiation. Different mechanisms and scenarios were identified: (1) Microplas- ticity generally starts at twin boundaries even at stresses as low as 70\% of the macroscopic yield strength, (2) transgranular slip activity intensively develops above the macroscopic yield stress, (3) intense slip activity develops near and parallel to 21\% of the twin boundaries intercepting NMIs, (4) 7\% of the twin boundaries inter- cepting NMIs lead to slip-assisted NMI cracking, (5) no transgranular slip activity participates in NMI cracking, (6) the fraction of cracked NMIs progressively increases with the load, and (7) within the NMIs that initiated cracks, 67\% cracked below 90\% of the macroscopic yield strength without the presence of slip activity in the neighboring grains. While slip-assisted NMI cracking was evidenced in the present study, most NMI cracking is due to strain incompatibility between NMIs and neighboring grains at the high end of the elastic regime without slip interaction.

}, keywords = {fatigue, High Resolution-Digital Image Correlation (HR-DIC), In-situ tensile testing, Non-metallic inclusions (NMIs), Twin boundary}, isbn = {9783030518349}, doi = {10.1007/978-3-030-51834-9}, url = {http://dx.doi.org/10.1007/978-3-030-51834-9_65}, author = {Texier, Damien and Stinville, Jean-Charles and Charpagne, Marie-agathe and Chen, Zhe and Valle, Valery and Villechaise, Patrick and Pollock, Tresa M. and Cormier, Jonathan}, editor = {Tin, Sammy and Hardy, Mark and Clews, Justin and Cormier, Jonathan and Feng, Qiang and Marcin, John and O{\textquoteright}Brien, Chris and Suzuki, Akane} } @article {1621, title = {Sustainability through alloy design: Challenges and opportunities}, journal = {Progress in Materials Science}, year = {2020}, pages = {100722}, abstract = {

Exciting metallurgical breakthroughs of the last decades alongside the development and wide-ranging availability of new and more capable experimental and theoretical tools for metals research demonstrate that we are witnessing the dawn of a new age in metals design. Historically, the discovery of new metallic materials has enabled the vast majority of the key engineering advances in human history. Current engineering challenges create an urgent need for new metallic materials to further our technological advances in multiple industries that are key to our existence. Yet, present data on metals processing clearly demonstrate the significant environmental impact of the metallurgical industry on our planet\&$\#$39;s future. There are numerous reports in which this impact and corresponding processing solutions are discussed. On the other hand, design of new metallic materials with improved property combinations can help address key environmental challenges in various ways. To this end, the goal of this review is to discuss the most urgent sustainability challenges that can be addressed with alloy design, to help orchestrate the increasing interest in metallurgical research to focus on these most critical challenges.

}, keywords = {Aluminum, High Entropy Alloys, Magnesium, Metallurgy, Shape memory alloys, Steel, Superalloys, Sustainability, Titanium}, issn = {00796425}, doi = {10.1016/j.pmatsci.2020.100722}, url = {https://doi.org/10.1016/j.pmatsci.2020.100722}, author = {Cann, Jaclyn L. and De Luca, Anthony and Dunand, David C. and Dye, David and Miracle, Daniel B. and Oh, Hyun Seok and Olivetti, Elsa A. and Pollock, Tresa M. and Poole, Warren J. and Yang, Rui and Tasan, C. Cem} } @conference {1616, title = {Tuning Strain Localization in Polycrystalline Nickel-Based Superalloys by Thermomechanical Processing}, booktitle = {Superalloys 2020}, year = {2020}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, abstract = {

Thermomechanical processing routes are used to produce microstructures that minimize plastic strain localization at the sub-grain scale in a polycrystalline \γ \− \γ\&$\#$39; nickel- based superalloy. This novel approach is made possible by the use of innovative experimental tools and statistical data analysis that capture slip events over large represen- tative fields of view. Results are correlated to conventional observations of fatigue crack initiation and early stage of propagation. The effect of coherent twin boundaries and primary \γ\&$\#$39; precipitates on fatigue properties and plastic localization is detailed.

}, keywords = {3D microstructure, Annealing twin boundaries, Nickel-based superalloy, Primary γ{\textquoteright} precipitates, Slip bands}, isbn = {9783030518349}, doi = {10.1007/978-3-030-51834-9}, url = {http://dx.doi.org/10.1007/978-3-030-51834-9_65}, author = {Charpagne, M. A. and Stinville, J. C. and Polonsky, A. T. and Echlin, M. P. and Murray, S. P. and Chen, Z. and Bozzolo, N. and Cormier, J. and Valle, V. and Pollock, T. M.}, editor = {Tin, Sammy and Hardy, Mark and Clews, Justin and Cormier, Jonathan and Feng, Qiang and Marcin, John and O{\textquoteright}Brien, Chris and Suzuki, Akane} } @conference {1601, title = {The Yield Strength Anomaly in Co-Ni Design Space}, booktitle = {Superalloys 2020}, year = {2020}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, abstract = {

A new computational approach to model precipitate compositions and properties in the CoNi-design space for yield strength anomaly prediction is presented. The antiphase boundary (APB) energies on {111} and {010} and the degree of elastic anisotropy are known to influence the yield strength anomaly. APB energies were estimated by a diffuse multi-layer fault (DMLF) model using the structural energies of proximate structures: L12, ca\′, and D023. The elastic moduli were calculated via the energy-strain approach using density functional theory calculations. (Ni1\−xCox)3(Al1\−yWy) was chosen as the model system, and Yoo\&$\#$39;s criterion is evaluated over the entire range ofcompositions to identify regions that exhibit the yield strength anomaly. (Ni0.65Co0.35)3(Al0.5W0.5) has the maximum APB (111) and any two-phase alloy (c + c') in Ni\–Co\–Al\–W system with this precipitate composition might exhibit higher strength upon shearing by a matrix dislocation. ThermoCalc was employed to identify stable L12 regions in (Ni1\−xCox)3(Al1\−yWy). The effect of Co on the yield strength anomaly was investigated experimen- tally in three (Ni1\−xCox)3Al alloys with L12 structure. All three alloys exhibited the yield strength anomaly, validat- ing the computational approach. The addition of Co provides solid solution strengthening to Ni3Al at room temperature; however, this contribution to the overall strength diminished as a function of temperature. CoNi-alloys displayed strengths similar to Ni3Al at elevated temperatures with Co addition resulting in a marginal increase in strength at the peak temperature. The present study elucidates that APB energies from a DMLF model combined with elastic moduli can be employed to predict yield strength anomaly using Yoo\&$\#$39;s criteria.

}, keywords = {Antiphase boundaries, CoNi-based superalloys, Yield strength anomaly}, isbn = {9783030518349}, doi = {10.1007/978-3-030-51834-9}, url = {http://dx.doi.org/10.1007/978-3-030-51834-9_65}, author = {Vamsi, K. V. and Murray, Sean P. and Pollock, Tresa M.}, editor = {Tin, Sammy and Hardy, Mark and Clews, Justin and Cormier, Jonathan and Feng, Qiang and Marcin, John and O{\textquoteright}Brien, Chris and Suzuki, Akane} } @article {1366, title = {Accurate reconstruction of EBSD datasets by a multimodal data approach using an evolutionary algorithm}, journal = {Materials Characterization}, volume = {150}, year = {2019}, pages = {184{\textendash}198}, abstract = {

A new method has been developed for the correction of the distortions and/or enhanced phase differentiation in Electron Backscatter Diffraction (EBSD) data. Using a multi-modal data approach, the method uses segmented images of the phase of interest (laths, precipitates, voids, inclusions) on images gathered by backscattered or secondary electrons of the same area as the EBSD map. The proposed approach then searches for the best transformation to correct their relative distortions and recombines the data in a new EBSD file. Speckles of the features of interest are first segmented in both the EBSD and image data modes. The speckle extracted from the EBSD data is then meshed, and the Covariance Matrix Adaptation Evolution Strategy (CMA-ES) is implemented to distort the mesh until the speckles superimpose. The quality of the matching is quantified via a score that is linked to the number of overlapping pixels in the speckles. The locations of the points of the distorted mesh are compared to those of the initial positions to create pairs of matching points that are used to calculate the polynomial function that describes the distortion the best. This function is then applied to un-distort the EBSD data, and the phase information is inferred using the data of the segmented speckle. Fast and versatile, this method does not require any human annotation and can be applied to large datasets and wide areas. Besides, this method requires very few assumptions concerning the shape of the distortion function. It can be used for the single compensation of the distortions or combined with the phase differentiation. The accuracy of this method is of the order of the pixel size. Some application examples in multiphase materials with feature sizes down to 1 \μm are presented, including Ti-6Al-4 V Titanium alloy, Rene 65 and additive manufactured Inconel 718 Nickel-base superalloys.

}, keywords = {CMA-ES, Distortions, EBSD, Image segmentation, Multi-modal data}, issn = {10445803}, doi = {10.1016/j.matchar.2019.01.033}, url = {https://doi.org/10.1016/j.matchar.2019.01.033}, author = {Charpagne, Marie Agathe and Strub, Florian and Pollock, Tresa M.} } @article {1386, title = {Computational homogenization for multiscale forward modeling of resonant ultrasound spectroscopy of heterogeneous materials}, journal = {Materials Characterization}, volume = {158}, year = {2019}, pages = {109945}, abstract = {

We present a computational framework for multiscale forward modeling of ultrasound resonance in heterogeneous materials that accounts for microstructure. The approach includes two steps. The first step is the accurate determination of the elastic properties of heterogeneous materials with finite element simulations on a representative volume element of the microstructure at the mesoscopic length scale. The second step is modeling resonance frequencies of a macroscopic component made of an effective homogeneous medium having the same elastic properties as the actual material with microstructure. The approach is validated in a case study on a Cu\–W two-phase composite, for which resonance frequencies predicted with the proposed framework are compared against the experimental measurements. The present multiscale modeling approach, involving computational homogenization and leveraging 3D microstructure data, showed better accuracy compared to classical Voigt/Reuss bounds often used for forward modeling of resonant ultrasound spectroscopy.

}, keywords = {Computational homogenization, Finite elements, Forward modeling, Non-destructive evaluation, Resonant ultrasound spectroscopy}, issn = {10445803}, doi = {10.1016/j.matchar.2019.109945}, url = {https://doi.org/10.1016/j.matchar.2019.109945}, author = {Latypov, Marat I. and Charpagne, Marie Agathe and Souther, Mason and Goodlet, Brent R. and Echlin, Mclean P. and Beyerlein, Irene J. and Pollock, Tresa M.} } @article {1516, title = {Correction of Electron Back-scattered Diffraction datasets using an evolutionary algorithm}, journal = {arXiv}, year = {2019}, pages = {1{\textendash}10}, abstract = {

In materials science and particularly electron microscopy, Electron Back-scatter Diffraction (EBSD) is a common and powerful mapping technique for collecting local crystallographic data at the sub-micron scale. The quality of the reconstruction of the maps is critical to study the spatial distribution of phases and crystallographic orientation relationships between phases, a key interest in materials science. However, EBSD data is known to suffer from distortions that arise from several instrument and detector artifacts. In this paper, we present an unsupervised method that corrects those distortions, and enables or enhances phase differentiation in EBSD data. The method uses a segmented electron image of the phases of interest (laths, precipitates, voids, inclusions) gathered using detectors that generate less distorted data, of the same area than the EBSD map, and then searches for the best transformation to correct the distortions of the initial EBSD data. To do so, the Covariance Matrix Adaptation Evolution Strategy (CMA-ES) is implemented to distort the EBSD until it matches the reference electron image. Fast and versatile, this method does not require any human annotation and can be applied to large datasets and wide areas, where the distortions are important. Besides, this method requires very little assumption concerning the shape of the distortion function. Some application examples in multiphase materials with feature sizes down to 1 \$\backslashmu\$m are presented, including a Titanium alloy and a Nickel-base superalloy.

}, url = {http://arxiv.org/abs/1903.02982}, author = {Strub, Florian and Charpagne, Marie-agathe and Pollock, Tresa M.} } @article {1356, title = {Dislocation dynamics in a nickel-based superalloy via in-situ transmission scanning electron microscopy}, journal = {Acta Materialia}, volume = {168}, year = {2019}, pages = {152{\textendash}166}, abstract = {

Micro-tensile specimens of nickel-based superalloy oligocrystals were tested in-situ in an scanning electron microscope in transmission mode (TSEM) enabling observation of dislocations. The dynamics of dislocation motion during tensile loading were captured and correlated with the measured intermittencies during plastic flow recorded by high load- and temporal-resolution sensors. This investigation in particular focused on the dislocation behavior near twin boundaries with different slip configurations. A multiplicity of deformation mechanisms at the dislocation scale were observed within individual slip bands, including precipitate shearing, dislocation decorrelation and antiphase boundary-coupled shearing. These processes affect strain localization near twin boundaries and provide new defect-level insights on plastic localization and fatigue crack initiation in these alloys.

}, keywords = {Dislocations dynamic, In-situ transmission scanning electron microscopy (TSEM), Nickel-based superalloy ren{\'e} 88DT, Plastic localization, STEM detector, Twin boundary}, issn = {13596454}, doi = {10.1016/j.actamat.2018.12.061}, url = {https://doi.org/10.1016/j.actamat.2018.12.061}, author = {Stinville, J. C. and Yao, Eric R. and Callahan, Patrick G. and Shin, Jungho and Wang, Fulin and Echlin, Mclean P. and Pollock, Tresa M. and Gianola, Daniel S.} } @article {1521, title = {New frontiers for the materials genome initiative}, journal = {npj Computational Materials}, volume = {5}, year = {2019}, pages = {1{\textendash}23}, abstract = {

The Materials Genome Initiative (MGI) advanced a new paradigm for materials discovery and design, namely that the pace of new materials deployment could be accelerated through complementary efforts in theory, computation, and experiment. Along with numerous successes, new challenges are inviting researchers to refocus the efforts and approaches that were originally inspired by the MGI. In May 2017, the National Science Foundation sponsored the workshop \“Advancing and Accelerating Materials Innovation Through the Synergistic Interaction among Computation, Experiment, and Theory: Opening New Frontiers\” to review accomplishments that emerged from investments in science and infrastructure under the MGI, identify scientific opportunities in this new environment, examine how to effectively utilize new materials innovation infrastructure, and discuss challenges in achieving accelerated materials research through the seamless integration of experiment, computation, and theory. This article summarizes key findings from the workshop and provides perspectives that aim to guide the direction of future materials research and its translation into societal impacts.

}, issn = {20573960}, doi = {10.1038/s41524-019-0173-4}, url = {http://dx.doi.org/10.1038/s41524-019-0173-4}, author = {de Pablo, Juan J. and Jackson, Nicholas E. and Webb, Michael A. and Chen, Long Qing and Moore, Joel E. and Morgan, Dane and Jacobs, Ryan and Pollock, Tresa and Schlom, Darrell G. and Toberer, Eric S. and Analytis, James and Dabo, Ismaila and DeLongchamp, Dean M. and Fiete, Gregory A. and Grason, Gregory M. and Hautier, Geoffroy and Mo, Yifei and Rajan, Krishna and Reed, Evan J. and Rodriguez, Efrain and Stevanovic, Vladan and Suntivich, Jin and Thornton, Katsuyo and Zhao, Ji Cheng} } @article {1496, title = {Short crack propagation from cracked non-metallic inclusions in a Ni-based polycrystalline superalloy}, journal = {Acta Materialia}, volume = {165}, year = {2019}, pages = {241{\textendash}258}, abstract = {

Fatigue cracks initiating from surface and sub-surface non-metallic inclusions (NMIs) have recently been demonstrated to be a necessary but not sufficient explanation for atypically short low-cycle fatigue life in Inconel 718 alloy at intermediate temperature. Therefore, the early stages of short crack propagation from surface NMIs were investigated in a crystallographic and two-dimensional versus three-dimensional morphological manner after room temperature low cycle fatigue (LCF) testing. In the present investigation, NMIs were purposely pre-cracked using different techniques to suppress the natural crack initiation period and thus the incubation period prior to the early stages of crack propagation. Under such fatigue testing conditions, different mechanisms of crack transmission from pre-cracked NMIs were identified: (i) no propagation, (ii) NMI/adjacent metallic grain interfacial debonding, (iii) transgranular crack propagation within the adjacent metallic grain. Focused-ion-beam cross-section observations of numerous fatigue tested NMIs aimed to define a morphological criterion for non-propagating NMIs. Large cracked NMIs at the surface (2c) with limited extension into the depth (a) did not propagate under such fatigue conditions for 2c/a ratio higher than 3. Furthermore, specific crystallographic relationships between NMIs and the adjacent metallic grain explained different crack propagation configurations from pre-cracked NMIs, i.e. interfacial debonding and transgranular crack propagation involving single or multiple-slip activity.

}, keywords = {Focus-ion-beam cross-section (FIB-cross section), Low cycle fatigue, Non-metallic inclusions, Short crack propagation, Superalloy 718DA}, issn = {13596454}, doi = {10.1016/j.actamat.2018.11.051}, author = {Texier, Damien and Stinville, Jean Charles and Echlin, Mclean P. and Pierret, St{\'e}phane and Villechaise, Patrick and Pollock, Tresa M. and Cormier, Jonathan} } @article {1431, title = {Advanced detector signal acquisition and electron beam scanning for high resolution SEM imaging}, journal = {Ultramicroscopy}, volume = {195}, year = {2018}, pages = {93{\textendash}100}, abstract = {

The advancement of materials science at the mesoscale requires improvements in both sampling volumes/areas and spatial resolution in order to make statistically significant measurements of microstructures that influence higher-order material properties, such as fatigue and fracture. Therefore, SEM-based techniques have become desirable due to improvements in imaging resolution, large sample handling capability, and flexibility for in-situ instrumentation. By using fast sampling of SEM electron detector signals, intrinsic beam scanning defects have been identified that are related to the response time of the SEM electron beam deflectors and electron detectors. Mitigation of these beam scanning defects using detector sampling approaches and an adaptive model for settling time is shown to produce higher resolution SEM images, at faster image acquisition times, with a means to quantify the different response functions for various beam deflectors and detectors including those for electrons and ions.

}, keywords = {High resolution digital image correlation, Image processing, Imaging defects, Scan generator, Scanning electron microscopy, SEM}, issn = {18792723}, doi = {10.1016/j.ultramic.2018.08.025}, url = {https://doi.org/10.1016/j.ultramic.2018.08.025}, author = {Lenthe, William C. and Stinville, Jean Charles and Echlin, Mclean P. and Chen, Zhe and Daly, Samantha and Pollock, Tresa M.} } @article {1441, title = {Competing Modes for Crack Initiation from Non-metallic Inclusions and Intrinsic Microstructural Features During Fatigue in a Polycrystalline Nickel-Based Superalloy}, journal = {Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science}, volume = {49}, year = {2018}, pages = {3865{\textendash}3873}, abstract = {

Cyclic fatigue experiments in the high and very high cycle fatigue regimes have been performed on a Ren\é 88DT polycrystalline nickel-based superalloy. The microstructural configurations that favor early strain localization and fatigue crack initiation at high temperature from 400\ \°C to 650\ \°C have been investigated. Competing failure modes are observed in the high to the very high cycle fatigue regime. Fatigue cracks initiate from non-metallic inclusions and from intrinsic internal microstructural features. Interestingly, as stresses are reduced into the very high cycle regime, there is a transition to initiation only at crystallographic facets. At higher stress in the high cycle fatigue regime, a significant fraction of specimens initiate cracks at non-metallic inclusions. This transition is analyzed with regard to microstructural features that favor strain localization and accumulate damage early during cycling.

}, isbn = {1166101847803}, issn = {10735623}, doi = {10.1007/s11661-018-4780-3}, url = {https://doi.org/10.1007/s11661-018-4780-3}, author = {Stinville, Jean Charles and Martin, Etienne and Karadge, Mallikarjun and Ismonov, Shak and Soare, Monica and Hanlon, Tim and Sundaram, Sairam and Echlin, McLean L.P. and Callahan, Patrick G. and Lenthe, William C. and Miao, Jiashi and Wessman, Andrew E. and Finlay, Rebecca and Loghin, Adrian and Marte, Judson and Pollock, Tresa M.} } @article {1316, title = {Creep Behavior of Quinary γ'-Strengthened Co-Based Superalloys}, journal = {Metallurgical and Materials Transactions A}, volume = {49}, year = {2018}, pages = {4090{\textendash}4098}, issn = {1073-5623}, doi = {10.1007/s11661-018-4768-z}, url = {http://link.springer.com/10.1007/s11661-018-4768-z}, author = {Rhein, Robert K. and Callahan, Patrick G. and Murray, Sean P. and Stinville, Jean-Charles and Titus, Michael S. and Van der Ven, Anton and Pollock, Tresa M.} } @article {1466, title = {Designing nickel base alloys for microstructural stability through low γ-γ' interfacial energy and lattice misfit}, journal = {Materials and Design}, volume = {140}, year = {2018}, pages = {249{\textendash}256}, abstract = {

An extended stability alloy design strategy for multicomponent \γ-\γ\′ nickel-base alloys with near-zero lattice misfit and as low as possible interfacial energy was investigated by isothermal annealing of two experimental alloys at 900 \°C for times up to 256 h. The coarsening behavior of the spherical \γ\′ precipitates and the phase compositions determined by atom probe tomography were utilized to exploit a modified Lifshitz-Slyozov-Wagner relationship to estimate the interfacial energies. The estimated interfacial energies are much lower than predicted by a CALPHAD-based software as well as those typically reported for multicomponent \γ-\γ\′ nickel alloys. Despite successfully minimizing the interfacial energy and \γ-\γ\′ lattice misfit, these factors alone were not sufficient to impart high temperature extended stability through reduced coarsening kinetics.

}, keywords = {Atom probe tomography, Interfacial energy, Precipitate coarsening, γ-γ' nickel-base alloy}, issn = {18734197}, doi = {10.1016/j.matdes.2017.11.065}, url = {http://dx.doi.org/10.1016/j.matdes.2017.11.065}, author = {Meher, S. and Carroll, M. C. and Pollock, T. M. and Carroll, L. J.} } @article {1311, title = {Elastic Properties of Novel Co- and CoNi-Based Superalloys Determined through Bayesian Inference and Resonant Ultrasound Spectroscopy}, journal = {Metallurgical and Materials Transactions A}, volume = {49A}, year = {2018}, month = {06/2018}, pages = {2324{\textendash}2339}, issn = {1543-1940}, doi = {10.1007/s11661-018-4575-6}, url = {https://doi.org/10.1007/s11661-018-4575-6}, author = {Goodlet, Brent R and Mills, Leah and Bales, Ben and Charpagne, Marie-agathe and Murray, Sean P and Lenthe, William C and Petzold, Linda and Pollock, Tresa M} } @article {1346, title = {Fatigue deformation in a polycrystalline nickel base superalloy at intermediate and high temperature: Competing failure modes}, journal = {Acta Materialia}, volume = {152}, year = {2018}, pages = {16{\textendash}33}, abstract = {

The microstructural configurations that favor early strain localization and fatigue crack initiation at intermediate and high temperature (400 \°C\–650 \°C) have been investigated using novel experimental techniques, including high resolution digital image correlation and transmission scanning electron microscopy. Cyclic fatigue experiments in the high and low cycle fatigue regimes have been performed on a Ren\é 88DT polycrystalline nickel-base superalloy at temperatures up to 650 \°C and compared to previous fatigue results obtained from tests in the very high cycle fatigue regime. Competing failure modes are observed along with an inversion in the temperature fatigue life dependence of fatigue strength from the low to high cycle fatigue regime. Oxidation-assisted processes are dominant at high applied stresses while cyclic plastic localization and accumulation govern fracture at low applied stresses. In addition, a second competing mode exists in the high and very high cycle fatigue regime from non-metallic inclusions as compared to internal intrinsic initiation sites. The grain-scale features that exhibit strain localization and crack initiation were investigated in detail. Transmission electron microscopy (TEM), transmission scanning electron microscopy (TSEM) and electron channeling contrast imaging have been conducted on samples removed from targeted regions with microstructural configurations that favor crack initiation to characterize the associated dislocation sub-structure and its evolution with temperature. Plasticity is observed to be less localized during cyclic loading at high temperature compared to room temperature. The microstructural features that drive initiation across the temperature range investigated are: twin-parent grains pairs that are at the upper end of the size distribution, are oriented for near maximum elastic modulus mismatch, and have high stresses along planes parallel to the twin boundaries.

}, keywords = {Coherent twin boundary, Elastic anisotropy, Fatigue crack initiation at intermediate and high temperature, High resolution digital image correlation, Microstructural effect, Polycrystalline microstructure, Ren{\'e} 88DT polycrystalline superalloy, Strain localization}, issn = {13596454}, doi = {10.1016/j.actamat.2018.03.035}, url = {https://doi.org/10.1016/j.actamat.2018.03.035}, author = {Stinville, Jean Charles and Martin, Etienne and Karadge, Mallikarjun and Ismonov, Shak and Soare, Monica and Hanlon, Tim and Sundaram, Sairam and Echlin, Mclean P. and Callahan, Patrick G. and Lenthe, William C. and Miller, V. M. and Miao, Jiashi and Wessman, Andrew E. and Finlay, Rebecca and Loghin, Adrian and Marte, Judson and Pollock, Tresa M.} } @article {1461, title = {High-Resolution Deformation Mapping Across Large Fields of View Using Scanning Electron Microscopy and Digital Image Correlation}, journal = {Experimental Mechanics}, volume = {58}, year = {2018}, pages = {1407{\textendash}1421}, abstract = {

This paper details the creation of experimental and computational frameworks to capture high-resolution, microscale deformation mechanisms and their relation to microstructure over large (mm-scale) fields of view. Scanning electron microscopy with custom automation and external beam control was used to capture 209 low-distortion micrographs of 360\ \μm \× 360\ \μm each, that were individually correlated using digital image correlation to obtain displacement/strain fields with a spatial resolution of 0.44\ \μm. Displacement and strain fields, as well as secondary electron images, were subsequently stitched to create a 5.7\ mm\ \×\ 3.4\ mm field of view containing 100 million (7678 \× 13,004) data points. This approach was demonstrated on Mg WE43 under uniaxial compression, where effective strain was shown to be relatively constant with respect to distance from the grain boundary, and a noticeable increase in the effective strain was found with an increase in the basal Schmid factor. The ability to obtain high-resolution deformations over statistically relevant fields of view enables large data analytics to examine interactions between microstructure, microscale strain localizations, and macroscopic properties.

}, keywords = {Alignment, Digital image correlation (DIC), Distortion, External scan, Stitching}, issn = {17412765}, doi = {10.1007/s11340-018-0419-y}, author = {Chen, Z. and Lenthe, W. and Stinville, J. C. and Echlin, M. and Pollock, T. M. and Daly, S.} } @article {1436, title = {Measurements of plastic localization by heaviside-digital image correlation}, journal = {Acta Materialia}, volume = {157}, year = {2018}, pages = {307{\textendash}325}, abstract = {

In polycrystalline metallic materials, quantitative and statistical assessment of the plasticity in relation to the microstructure is necessary to understand the deformation processes during mechanical loading. Plastic deformation often localizes into physical slip bands at the sub-grain scale. Detrimental microstructural configurations that result in the formation and evolution of slip bands during loading require advanced strain mapping techniques for the identification of these atomically sharp discontinuities. A new discontinuity-tolerant DIC method, Heaviside-DIC, has been developed to account for discontinuities in the displacement field. Displacement fields have been measured at the scale of the physical slip bands over large areas in nickel-based superalloys by high resolution scanning electron microscopy digital image correlation (SEM DIC). However, conventional DIC methods cannot quantitatively measure plastic localization in the presence of discontinuous kinematic fields such as those produced by slip bands. The Heaviside-DIC technique can autonomously detect discontinuities, providing information about their location, inclination, and identify slip systems (in combination with orientation mapping). Using Heaviside-DIC, discontinuities are physically evaluated as sharp shear-localization events, allowing for the quantitative measure of strain amplitude nearby the discontinuities. Measurements using the new Heaviside-DIC technique are compared to conventional DIC methods for identical materials and imaging conditions.

}, keywords = {Discontinuities measurements, High resolution digital image correlation, Ren{\'e} 88DT polycrystalline superalloy, Scanning electron microscopy, Slip band offset, Slip band shearing, Slip system identification, Strain localization}, issn = {13596454}, doi = {10.1016/j.actamat.2018.07.013}, url = {https://doi.org/10.1016/j.actamat.2018.07.013}, author = {Bourdin, F. and Stinville, J. C. and Echlin, M. P. and Callahan, P. G. and Lenthe, W. C. and Torbet, C. J. and Texier, D. and Bridier, F. and Cormier, J. and Villechaise, P. and Pollock, T. M. and Valle, V.} } @article {1481, title = {Prediction of tensile stiffness and strength of Ti-6Al-4V using instantiated volume elements and crystal plasticity}, journal = {Acta Materialia}, volume = {157}, year = {2018}, pages = {21{\textendash}32}, abstract = {

Based on simulations of tensile tests, the macroscopic stiffness and strength of the \α phase of Ti-6Al-4V are estimated. Sets of virtual samples are instantiated using characterization data from three-dimensional electron back-scattered diffraction (EBSD) scans collected with the TriBeam microscope and local properties extracted from in situ loading high-energy x-ray diffraction (HEXD) experiments. The simulations use a crystal-scale finite element framework to compute the mechanical response of the virtual samples under tensile loading. From the simulation data, mechanical properties are extracted from volume elements ranging in size from a fraction of the gage section to its entire length. To detect macroscopic yield, a flood-fill algorithm is used to identify a zone of plastically deformed finite elements extending through a volume element. Trends in the estimated properties as functions of the volume element size are examined. The lower bound of volume element size necessary to replicate experimentally measured macroscale properties is indicated. The technique and results provide a guideline for estimating macroscale property values in components designed with size smaller than the lower bound due to constraint.

}, keywords = {Crystal plasticity finite element, Stiffness, Titanium, Volume element size, Yield detection}, issn = {13596454}, doi = {10.1016/j.actamat.2018.07.011}, url = {https://doi.org/10.1016/j.actamat.2018.07.011}, author = {Chatterjee, Kamalika and Echlin, Mclean P. and Kasemer, Matthew and Callahan, Patrick G. and Pollock, Tresa M. and Dawson, Paul} } @article {1176, title = {Transmission Scanning Electron Microscopy: Defect Observations and Image Simulations}, journal = {Ultramicroscopy }, volume = {186}, year = {2018}, chapter = {49}, doi = {https://doi.org/10.1016/j.ultramic.2017.11.004}, author = {Callahan, PG and Stinville, JC and Yao, ER and Echlin, MP and Titus, MS and De Graef, M and Pollock, TM and Gianola, DS} } @article {1446, title = {Electrically pumped continuous wave quantum dot lasers epitaxially grown on patterned, on-Axis (001) Si}, journal = {Optics Express}, volume = {25}, year = {2017}, pages = {3927{\textendash}3934}, keywords = {III-V on Silicon, Monolithic Integration, Quantum dot lasers, Silicon Photonics}, isbn = {9784885523069}, issn = {08999406}, doi = {10.1364/ol.42.000338}, author = {Norman, Justin and Kennedy, M.J. and Selvidge, Jennifer and Li, Quang and Wan, Yating and Liu, Alan Y. and Callahan, Patrick G. and Echlin, Mclean P. and Pollock, Tresa M. and Lau, Kei May and Gossard, Arthur C. and Bowers, John E.} } @article {1221, title = {Measurement of Strain Localization Resulting from Monotonic and Cyclic Loading at 650 oC in Nickel Base Superalloys}, journal = {Experimental Mechanics}, volume = {57}, year = {2017}, pages = {1289{\textendash}1309}, doi = {10.1007/s11340-017-0286-y}, author = {Stinville, J. C. and Echlin, M. P. and Callahan, P. G. and Miller, V. M. and Texier, D. and Bridier, F. and Bocher, P. and Pollock, T. M.} } @article {1236, title = {Microstructural Statistics for Fatigue Crack Initiation in Polycrystalline Nickel-base Superalloys}, journal = {International Journal of Fracture}, volume = {208}, year = {2017}, pages = {240}, chapter = {221}, doi = {https://doi.org/10.1007/s10704-017-0241-z}, url = {https://link.springer.com/article/10.1007/s10704-017-0241-z}, author = {Stinville, JC and Lenthe, William C and Echlin, MP and Callahan, PG and Texier, Damien and Pollock, TM} } @article {1201, title = {Reconstruction of Laser-Induced Surface Topography from Electron Backscatter Diffraction Patterns}, journal = {Microscopy and Microanalysis}, volume = {23}, year = {2017}, pages = {730{\textendash}740}, doi = {10.1017/s1431927617012326}, author = {Callahan, Patrick G. and Echlin, Mclean P. and Pollock, Tresa M. and Graef, Marc De} } @article {1241, title = {Three-dimensional texture visualization approaches: theoretical analysis and examples}, journal = {Journal of Applied Crystallography}, volume = {50}, year = {2017}, month = {Jul}, pages = {430{\textendash}440}, doi = {10.1107/s1600576717001157}, author = {Callahan, Patrick G. and Echlin, Mclean and Pollock, Tresa M. and Singh, Saransh and Graef, Marc De} } @article {douglas2016magnetic, title = {Magnetic hardening and antiferromagnetic/ferromagnetic phase coexistence in Mn 1- x Fe x Ru 2 Sn Heusler solid solutions}, journal = {Physical Review B}, volume = {94}, number = {9}, year = {2016}, pages = {094412}, publisher = {American Physical Society}, author = {Douglas, Jason E and Levin, Emily E and Pollock, Tresa M and Castillo, Juan C and Adler, Peter and Felser, Claudia and Kr{\"a}mer, Stephan and Page, Katharine L and Seshadri, Ram} } @article {texier2016microstructural, title = {Microstructural features controlling the variability in low-cycle fatigue properties of alloy Inconel 718DA at intermediate temperature}, journal = {Metallurgical and Materials Transactions A}, volume = {47}, number = {3}, year = {2016}, pages = {1096{\textendash}1109}, publisher = {Springer US}, author = {Texier, Damien and G{\'o}mez, Ana Casanova and Pierret, St{\'e}phane and Franchet, Jean-Michel and Pollock, Tresa M and Villechaise, Patrick and Cormier, Jonathan} } @article {meher2016solute, title = {Solute partitioning in multi-component $\gamma$/$\gamma$' Co{\textendash}Ni-base superalloys with near-zero lattice misfit}, journal = {Scripta Materialia}, volume = {113}, year = {2016}, pages = {185{\textendash}189}, publisher = {Pergamon}, author = {Meher, S and Carroll, LJ and Pollock, TM and Carroll, MC} } @article {meher2016understanding, title = {Understanding of Inverse Coarsening of $\gamma${\textquoteright}precipitates in Ni-base Superalloys}, journal = {Microscopy and Microanalysis}, volume = {22}, number = {S3}, year = {2016}, pages = {1258{\textendash}1259}, publisher = {Cambridge University Press}, author = {Meher, Subhashish and Aagesen, Larry K and Carroll, Laura J and Carroll, Mark C and Pollock, Tresa M} } @article {steuer2015benefits, title = {Benefits of high gradient solidification for creep and low cycle fatigue of AM1 single crystal superalloy}, journal = {Materials Science and Engineering: A}, volume = {645}, year = {2015}, pages = {109{\textendash}115}, publisher = {Elsevier}, author = {Steuer, S and Villechaise, P and Pollock, TM and Cormier, J} } @article {carpenter2015bulk, title = {Bulk texture evolution of nanolamellar Zr{\textendash}Nb composites processed via accumulative roll bonding}, journal = {Acta Materialia}, volume = {92}, year = {2015}, pages = {97{\textendash}108}, publisher = {Pergamon}, author = {Carpenter, JS and Nizolek, T and McCabe, RJ and Knezevic, M and Zheng, SJ and Eftink, BP and Scott, JE and Vogel, SC and Pollock, TM and Mara, NA and others} } @article {callahan2015determination, title = {Determination of Surface Topography from Laser Ablation using EBSD}, journal = {Microscopy and Microanalysis}, volume = {21}, number = {S3}, year = {2015}, pages = {2369{\textendash}2370}, publisher = {Cambridge University Press}, author = {Callahan, PG and Echlin, MP and Pollock, TM and De Graef, M} } @article {rhein2015role, title = {Role of vibrational and configurational excitations in stabilizing the L 1 2 structure in Co-rich Co-Al-W alloys}, journal = {Physical Review B}, volume = {92}, number = {17}, year = {2015}, pages = {174117}, publisher = {American Physical Society}, author = {Rhein, Robert K and Dodge, Philip C and Chen, Min-Hua and Titus, Michael S and Pollock, Tresa M and Van der Ven, Anton} } @article {carpenter2015suppression, title = {The suppression of instabilities via biphase interfaces during bulk fabrication of nanograined Zr}, journal = {Materials Research Letters}, volume = {3}, number = {1}, year = {2015}, pages = {50{\textendash}57}, publisher = {Taylor \& Francis}, author = {Carpenter, JS and Nizolek, TJ and McCabe, RJ and Zheng, SJ and Scott, JE and Vogel, SC and Mara, NA and Pollock, TM and Beyerlein, IJ} } @article {steuer2014creep, title = {Creep behavior under isothermal and non-isothermal conditions of AM3 single crystal superalloy for different solutioning cooling rates}, journal = {Materials Science and Engineering: A}, volume = {601}, year = {2014}, pages = {145{\textendash}152}, publisher = {Elsevier}, author = {Steuer, S and Hervier, Z and Thabart, S and Castaing, C and Pollock, TM and Cormier, J} } @conference {ardeljan2014multi, title = {A multi-scale model for texture development in Zr/Nb nanolayered composites processed by accumulative roll bonding}, booktitle = {IOP Conference Series: Materials Science and Engineering}, volume = {63}, number = {1}, year = {2014}, pages = {012170}, publisher = {IOP Publishing}, organization = {IOP Publishing}, author = {Ardeljan, M and Knezevic, M and Nizolek, T and Beyerlein, IJ and Zheng, SJ and Carpenter, JS and McCabe, RJ and Mara, NA and Pollock, TM} } @article {douglas2014nanoscale, title = {Nanoscale structural heterogeneity in Ni-rich half-Heusler TiNiSn}, journal = {Journal of Applied Physics}, volume = {116}, number = {16}, year = {2014}, pages = {163514}, publisher = {AIP Publishing}, author = {Douglas, Jason E and Chater, Philip A and Brown, Craig M and Pollock, Tresa M and Seshadri, Ram} } @article {allison2013integrated, title = {Integrated Computational Materials Engineering (ICME): Implementing ICME in the Aerospace, Automotive, and Maritime Industries}, journal = {A Study Organized by The Minerals, Metals \& Materials Society. The Minerals, Metals \& Materials Society, Warrendale, PA}, volume = {15086}, year = {2013}, author = {Allison, John and Cowles, Brad and DeLoach, John and Pollock, Tresa and Spanos, George} } @article {beyerlein2013interface, title = {Interface-driven microstructure development and ultra high strength of bulk nanostructured Cu-Nb multilayers fabricated by severe plastic deformation}, journal = {Journal of materials research}, volume = {28}, number = {13}, year = {2013}, pages = {1799{\textendash}1812}, publisher = {Cambridge University Press}, author = {Beyerlein, Irene J and Mara, Nathan A and Carpenter, John S and Nizolek, Thomas and Mook, William M and Wynn, Thomas A and McCabe, Rodney J and Mayeur, Jason R and Kang, Keonwook and Zheng, Shijian and others} } @article {terbush2012dependence, title = {The dependence of creep behavior on elemental partitioning in Mg-5Al-3Ca-xSn alloys}, journal = {Metallurgical and Materials Transactions A}, volume = {43}, number = {9}, year = {2012}, pages = {3120{\textendash}3134}, publisher = {Springer US}, author = {TerBush, Jessica R and Chen, Olivia H and Jones, J Wayne and Pollock, Tresa M} } @article {beyerlein2012structure, title = {Structure{\textendash}property{\textendash}functionality of bimetal interfaces}, journal = {Jom}, volume = {64}, number = {10}, year = {2012}, pages = {1192{\textendash}1207}, publisher = {Springer US}, author = {Beyerlein, IJ and Mara, NA and Wang, J and Carpenter, JS and Zheng, SJ and Han, WZ and Zhang, RF and Kang, K and Nizolek, T and Pollock, TM} } @article {terbush2011creep, title = {Creep and Elemental Partitioning Behavior of Mg-Al-Ca-Sn Alloys with the Addition of Sr}, journal = {Magnesium Technology 2011}, year = {2011}, pages = {215{\textendash}222}, publisher = {John Wiley \& Sons, Inc.}, author = {TerBush, Jessica R and Chen, Olivia H and Jones, J Wayne and Pollock, Tresa M} } @article {liu2011situ, title = {In situ synchrotron X-ray imaging of high-cycle fatigue crack propagation in single-crystal nickel-base alloys}, journal = {Acta Materialia}, volume = {59}, number = {13}, year = {2011}, pages = {5103{\textendash}5115}, publisher = {Elsevier}, author = {Liu, L and Husseini, NS and Torbet, CJ and Lee, W-K and Clarke, R and Jones, JW and Pollock, TM} } @conference {terbush2010elemental, title = {Elemental partitioning and microstructure of Mg-Al-Ca-Sn quaternary alloys}, booktitle = {TMS 2010: Aluminium and Magnesium (TMS 14 February 2010 to 18 February 2010)}, year = {2010}, pages = {1{\textendash}5}, publisher = {TMS}, organization = {TMS}, author = {TerBush, Jessica and Chen, Olivia and Jones, J and Pollock, Tresa} } @article {van2010elemental, title = {Elemental partitioning of platinum group metal containing Ni-base superalloys using electron microprobe analysis and atom probe tomography}, journal = {Acta Materialia}, volume = {58}, number = {6}, year = {2010}, pages = {1952{\textendash}1962}, publisher = {Pergamon}, author = {Van Sluytman, JS and La Fontaine, A and Cairney, JM and Pollock, TM} } @article {chen2010pulsed, title = {Pulsed-terahertz reflectometry for health monitoring of ceramic thermal barrier coatings}, journal = {Optics express}, volume = {18}, number = {4}, year = {2010}, pages = {3477{\textendash}3486}, publisher = {Optical Society of America}, author = {Chen, Chia-Chu and Lee, Dong-Joon and Pollock, Tresa and Whitaker, John F} } @booklet {brundidge2010real, title = {Real Time Synchrotron Radiography of High Temperature High Cycle Fatigue Crack Growth in Single-Crystal Nickel-Base Superalloys}, howpublished = {Minerals, Metals and Materials Society/AIME, 420 Commonwealth Dr., P. O. Box 430 Warrendale PA 15086 USA.[np]. 14-18 Feb}, year = {2010}, publisher = {Minerals, Metals and Materials Society/AIME, 420 Commonwealth Dr., P. O. Box 430 Warrendale PA 15086 USA}, author = {Brundidge, Clinique L and Husseini, Naji and Hanson, Erik and Torbet, Chris and Clarke, Roy and Jones, JWayne and Pollock, Tresa} } @article {cao2009microstructural, title = {Microstructural evolution and failure characteristics of a NiCoCrAlY bond coat in {\textquotedblleft}hot spot{\textquotedblright} cyclic oxidation}, journal = {Acta Materialia}, volume = {57}, number = {13}, year = {2009}, pages = {3885{\textendash}3894}, publisher = {Elsevier}, author = {Cao, F and Tryon, B and Torbet, CJ and Pollock, TM} } @conference {white2009time, title = {TIME DOMAIN TERAHERTZ NON-DESTRUCTIVE EVALUATION OF AEROTURBINE BLADE THERMAL BARRIER COATINGS}, booktitle = {REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION: Proceedings of the 35th Annual Review of Progress in Quantitative Nondestructive Evaluation}, volume = {1096}, number = {1}, year = {2009}, pages = {434{\textendash}439}, publisher = {AIP Publishing}, organization = {AIP Publishing}, author = {White, Jeffrey and Fichter, G and Chernovsky, A and Whitaker, John F and Das, D and Pollock, Tresa M and Zimdars, David} } @article {cao2008creep, title = {Creep deformation mechanisms in Ru-Ni-Al ternary B2 alloys}, journal = {Metallurgical and Materials Transactions A}, volume = {39}, number = {1}, year = {2008}, pages = {39{\textendash}49}, publisher = {Springer}, author = {Cao, F and Pollock, TM} } @article {kumah2008situ, title = {In Situ Imaging of High Cycle Fatigue Crack Growth in Single Crystal Nickel-Base Superalloys by Synchrotron X-Radiation}, journal = {Ann Arbor}, volume = {1001}, year = {2008}, pages = {48109}, author = {Kumah, Divine P and Clarke, Roy and Pollock, Tresa M and Jones, J Wayne} } @article {liu2008situ, title = {In situ imaging of high cycle fatigue crack growth in single crystal nickel-base superalloys by synchrotron X-radiation}, journal = {Journal of Engineering Materials and Technology}, volume = {130}, number = {2}, year = {2008}, pages = {021008}, publisher = {American Society of Mechanical Engineers}, author = {Liu, Liu and Husseini, Naji S and Torbet, Christopher J and Kumah, Divine P and Clarke, Roy and Pollock, Tresa M and Jones, J Wayne} } @article {carroll2008interfacial, title = {Interfacial Dislocation Networks and creep in directional coarsened Ru-containing nickel-base single-crystal superalloys}, journal = {Metallurgical and Materials Transactions A}, volume = {39}, number = {6}, year = {2008}, pages = {1290{\textendash}1307}, publisher = {Springer US}, author = {Carroll, LJ and Feng, Q and Pollock, TM} } @conference {pollock2008intermetallic, title = {Intermetallic Bond Coats: Systems Compatibility and Platinum-Group Metal Additions}, booktitle = {MRS Proceedings}, volume = {1128}, year = {2008}, pages = {1128{\textendash}U06}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, author = {Pollock, Tresa and Widrevitz, Dan and Pong, Russell and Cao, Fang and Tryon, Bryan} } @article {husseini2008mapping, title = {Mapping single-crystal dendritic microstructure and defects in nickel-base superalloys with synchrotron radiation}, journal = {Acta Materialia}, volume = {56}, number = {17}, year = {2008}, pages = {4715{\textendash}4723}, publisher = {Pergamon}, author = {Husseini, Naji S and Kumah, Divine P and Jian, Z Yi and Torbet, Christopher J and Arms, Dohn A and Dufresne, Eric M and Pollock, Tresa M and Jones, J Wayne and Clarke, Roy} } @conference {chen2008terahertz, title = {Terahertz characterization of interfacial oxide layers and voids for health monitoring of ceramic coatings}, booktitle = {2009 34th International Conference on Infrared, Millimeter, and Terahertz Waves}, year = {2008}, author = {Chen, Chia-Chu and Lee, Dong-Joon and Pollock, Tresa and Whitaker, John F} } @conference {white2008time, title = {Time-domain terahertz mapping of thickness and degradation of aircraft turbine blade thermal barrier coatings}, booktitle = {Conference on Lasers and Electro-Optics}, year = {2008}, pages = {CThN7}, publisher = {Optical Society of America}, organization = {Optical Society of America}, author = {White, Jeffrey and Fichter, G and Chernovsky, A and Zimdars, David A and Whitaker, John F and Das, D and Pollock, Tresa M} } @conference {cao2007compression, title = {COMPRESSION CREEP BEHAVIOR OF B 2 AL-NI-RU TERNARY ALLOYS}, booktitle = {Advanced Intermetallic-Based Alloys(MRS Symposium Proceedings Series Volume 980)}, volume = {980}, year = {2007}, pages = {45{\textendash}50}, author = {Cao, Fang and Pollock, Tresa M} } @article {feng2007cyclic, title = {Cyclic oxidation of Ru-containing single crystal superalloys at 1100 C}, journal = {Materials Science and Engineering: A}, volume = {458}, number = {1}, year = {2007}, pages = {184{\textendash}194}, publisher = {Elsevier}, author = {Feng, Q and Tryon, B and Carroll, LJ and Pollock, TM} } @article {cao2007deformation, title = {Deformation mechanisms in a Ru{\textendash}Ni{\textendash}Al ternary B2 intermetallic alloy}, journal = {Acta materialia}, volume = {55}, number = {8}, year = {2007}, pages = {2715{\textendash}2727}, publisher = {Elsevier}, author = {Cao, F and Pollock, TM} } @article {ma2007development, title = {Development of $\gamma$ phase stacking faults during high temperature creep of Ru-containing single crystal superalloys}, journal = {Acta Materialia}, volume = {55}, number = {17}, year = {2007}, pages = {5802{\textendash}5812}, publisher = {Pergamon}, author = {Ma, S and Carroll, L and Pollock, TM} } @article {carroll2007elemental, title = {Elemental partitioning in Ru-containing nickel-base single crystal superalloys}, journal = {Materials Science and Engineering: A}, volume = {457}, number = {1}, year = {2007}, pages = {292{\textendash}299}, publisher = {Elsevier}, author = {Carroll, LJ and Feng, Q and Mansfield, JF and Pollock, TM} } @conference {wang2007influence, title = {Influence of Ru and Cr on the heat-treated microstructure of Ni-based superalloys}, booktitle = {Materials science forum}, volume = {546}, year = {2007}, pages = {1207{\textendash}1210}, publisher = {Trans Tech Publications}, organization = {Trans Tech Publications}, author = {Wang, WB and Feng, Qiang and Carroll, LJ and Wang, YL and Chen, Guo Liang and Pollock, TM} } @article {cao2007oxidation, title = {Oxidation of ruthenium aluminide-based alloys: The role of microstructure and platinum additions}, journal = {Intermetallics}, volume = {15}, number = {1}, year = {2007}, pages = {34{\textendash}43}, publisher = {Elsevier}, author = {Cao, F and Nandy, TK and Stobbe, D and Pollock, TM} } @conference {cao2006compression, title = {Compression Creep Behavior of B2 AL-Ni-Ru Ternary Alloys}, booktitle = {MRS Proceedings}, volume = {980}, year = {2006}, pages = {0980{\textendash}II01}, publisher = {Cambridge University Press}, organization = {Cambridge University Press}, author = {Cao, Fang and Pollock, Tresa M} } @article {cao2006experimental, title = {Experimental investigation and thermodynamic modelling of the Mg{\textendash}Al-rich region of the Mg{\textendash}Al{\textendash}Sr System}, journal = {Zeitschrift f{\"u}r Metallkunde}, volume = {97}, number = {4}, year = {2006}, pages = {422{\textendash}428}, publisher = {Carl Hanser Verlag}, author = {Cao, Hongbo and Zhu, Jun and Zhang, Chuan and Wu, Kaisheng and Saddock, Nicholas D and Jones, J Wayne and Pollock, Tresa M and Schmid-Fetzer, Rainer and Chang, Y Austin} } @article {carroll2006high, title = {High refractory, low misfit Ru-containing single-crystal superalloys}, journal = {Metallurgical and Materials Transactions A}, volume = {37}, number = {10}, year = {2006}, pages = {2927{\textendash}2938}, publisher = {Springer}, author = {Carroll, LJ and Feng, Q and Mansfield, JF and Pollock, TM} } @article {tryon2006ruthenium, title = {Ruthenium-containing bond coats for thermal barrier coating systems}, journal = {JoM}, volume = {58}, number = {1}, year = {2006}, pages = {53{\textendash}59}, publisher = {Springer}, author = {Tryon, B and Cao, F and Murphy, KS and Levi, CG and Pollock, TM} } @article {feng2006soldification, title = {Soldification segregation in ruthenium-containing nickel-base superalloys}, journal = {Metallurgical and Materials Transactions A}, volume = {37}, number = {6}, year = {2006}, pages = {1949{\textendash}1962}, publisher = {Springer-Verlag}, author = {Feng, Q and Carroll, LJ and Pollock, TM} } @article {saddock2005solidification, title = {Solidification and Microstructure of Mg-Al-(Ca, Sr, Ce, La) Ternary Alloys}, journal = {Essential Readings in Magnesium Technology}, year = {2005}, pages = {199{\textendash}204}, publisher = {John Wiley \& Sons, Inc.}, author = {Saddock, ND and Suzuki, A and Wu, K and Wildy, SC and Chang, YA and Pollock, TM and Jones, JW} } @conference {shyam2004development, title = {Development of ultrasonic fatigue for rapid, high temperature fatigue studies in turbine engine materials}, booktitle = {10th International Symposium on Superalloys, Champion, PA, September}, year = {2004}, pages = {19{\textendash}23}, author = {Shyam, A and Torbet, CJ and Jha, SK and Larsen, JM and Caton, MJ and Szczepanski, CJ and Pollock, TM and Jones, JW} } @article {cerreta2004dynamic, title = {Dynamic deformation and damage in cast $\gamma$-TiAl during taylor cylinder impact: Experiments and model validation}, journal = {Metallurgical and Materials Transactions A}, volume = {35}, number = {9}, year = {2004}, pages = {2557{\textendash}2566}, publisher = {Springer}, author = {Cerreta, E and Chen, SR and Gray III, GT and Pollock, TM} } @article {xiao2004effect, title = {Effect of Boron Concentration on Fatigue Crack Propagation Resistance and Low Cycle Fatigue Properties of Inconel 718, Superalloys 2004, KA Green, H}, journal = {Harada, TE Howson, TM Pollock, RC Reed, JJ Schirra, and S. Walston, Ed., TMS, Warrendale, PA}, year = {2004}, pages = {275{\textendash}281}, author = {Xiao, L and Chen, DL and Chaturvedi, MC} } @article {walston2004joint, title = {Joint development of a fourth generation single crystal superalloy}, year = {2004}, author = {Walston, S and Cetel, A and MacKay, R and OHara, K and Duhl, D and Dreshfield, R} } @article {cerreta2004symposium, title = {Symposium on Dynamic Deformation: Constitutive Modeling, Grain Size, and Other Effects{\textendash}In Honor of Prof. Ronald W. Armstrong-Dynamic Deformation and Damage in Cast g-TiAl during Taylor Cylinder}, journal = {Metallurgical and Materials Transactions-Series A}, volume = {35}, number = {9}, year = {2004}, pages = {2557{\textendash}2566}, publisher = {Warrendale, PA: Minerals, Metals \& Materials Society; Materials Park, OH: ASM International, c1994-}, author = {Cerreta, E and Gray, GT and Chen, SR and Pollock, TM} } @article {rishel1998cast, title = {Cast structure and property variability in gamma titanium aluminides}, journal = {Intermetallics}, volume = {6}, number = {7}, year = {1998}, pages = {629{\textendash}636}, publisher = {Elsevier}, author = {Rishel, LL and Biery, NE and Raban, R and Gandelsman, VZ and Pollock, TM and Cramb, AW} }