@article {2196, title = {Navigating the BCC-B2 refractory alloy space: Stability and thermal processing with Ru-B2 precipitates}, journal = {Acta Materialia}, volume = {265}, year = {2024}, pages = {119628}, abstract = {

Refractory multi-principal element alloys (RMPEAs) could provide next-generation high temperature alloys, but their ductility and high temperature strength need significant improvement. Emulating superalloy \γ-\γ\’ microstructures, RMPEAs combining a ductile BCC matrix with embedded B2 precipitates for strengthening could meet this goal. Two-phase BCC-B2 RMPEAs have recently been demonstrated, but the B2 phase typically exhibits insufficient thermodynamic stability for operating temperatures \≥1300 \°C. Using high-throughput CALPHAD predictions, we screen across 3,500 potential BCC-B2 systems. Promising compositions are predicted for alloys combining Ru-based B2s with refractory BCC elements. A total of 20 such compositions were arc-melted to characterize their as-cast and heat-treated microstructures. In these alloys, the RuHf B2 exhibits exceptional stability beyond 1900 \°C but cannot be solutionized. By contrast, RuTi does solutionize and reprecipitate between 1300 and 1900 \°C, providing a robust thermal processing pathway. RuAl can be solutionized but also tends to form competing intermetallic phases. Altogether, Ru-B2 RMPEAs offer great design flexibility and surpass the stability and thermal processability of previously studied BCC-B2 refractory alloys.

}, keywords = {B2 phase, Calphad, Combinatorial, High temperature materials, Precipitation strengthening, Refractory multi principal element alloys, Thermal processing}, issn = {1359-6454}, doi = {https://doi.org/10.1016/j.actamat.2023.119628}, url = {https://www.sciencedirect.com/science/article/pii/S1359645423009564}, author = {Sebastian A. Kube and Carolina Frey and Chiyo McMullin and Ben Neuman and Kaitlyn M. Mullin and Tresa M. Pollock} } @article {1906, title = {In situ crack opening displacement growth rates of SiC/SiC ceramic matrix minicomposites}, journal = {Journal of the European Ceramic Society}, volume = {43}, year = {2023}, month = {02}, doi = {10.1016/j.jeurceramsoc.2023.01.061}, author = {Muir, C. and Swaminathan, B. and Musaffar, Abed and McCarthy, N.R. and Almansour, Amjad and Pollock, T.m. and Kiser, J.D. and Smith, C. and Daly, S. and Sevener, Kathleen} } @article {1846, title = {Inducing skyrmion flop transitions in Co 8 Zn 8 Mn 4 at room temperature}, journal = {Physical Review Materials}, volume = {7}, year = {2023}, month = {04}, doi = {10.1103/PhysRevMaterials.7.044401}, author = {Meynell, Simon and Eggeler, Yolita and Bocarsly, Joshua and Kitchaev, Daniil and Rhodes, Bailey and Pollock, Tresa and Wilson, Stephen and Ven, Anton and Seshadri, Ram and Graef, Marc and Jayich, Ania and Gianola, Daniel} } @article {1886, title = {Minor Elements and Solidification Cracking During Laser Powder-Bed Fusion of a High γ' CoNi-Base Superalloy}, journal = {Metallurgical and Materials Transactions}, volume = {54}, year = {2023}, month = {02}, pages = {1-14}, doi = {10.1007/s11661-023-06957-6}, author = {Raeker, Evan and Pusch, Kira and Forsik, St{\'e}phane and Zhou, Ning and Dicus, Austin and Ren, Qing-Qiang and Poplawsky, Jonathan and Kirka, M. and Pollock, Tresa} } @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 {1851, title = {Perspective: Machine learning in experimental solid mechanics}, journal = {Journal of the Mechanics and Physics of Solids}, volume = {173}, year = {2023}, month = {04}, pages = {105231}, doi = {10.1016/j.jmps.2023.105231}, author = {Brodnik, N.R. and Muir, C. and Tulshibagwale, N. and Rossin, J. and Echlin, M.P. and Hamel, C.M. and Kramer, S.L.B. and Pollock, T.m. and Kiser, J.D. and Smith, C. and Daly, S.H.} } @article {1891, title = {Quantitative Benchmarking of Acoustic Emission Machine Learning Frameworks for Damage Mechanism Identification}, journal = {Integrating Materials and Manufacturing Innovation}, year = {2023}, month = {02}, pages = {1-12}, doi = {10.1007/s40192-023-00293-8}, author = {Muir, C. and Tulshibagwale, N. and Furst, A. and Swaminathan, B. and Almansour, Amjad and Sevener, Kathleen and Presby, Michael and Kiser, J. and Pollock, T. and Daly, S. and Smith, C.} } @article {2016, title = {3D Grain Shape Generation in Polycrystals Using Generative Adversarial Networks}, journal = {Integrating Materials and Manufacturing Innovation}, volume = {11}, year = {2022}, month = {01}, doi = {10.1007/s40192-021-00244-1}, author = {Jangid, Devendra and Brodnik, Neal and Khan, Amil and Goebel, Michael and Echlin, Mclean and Pollock, Tresa and Daly, Samantha and Manjunath, B.} } @article {1911, title = {Adaptable physics-based super-resolution for electron backscatter diffraction maps}, journal = {npj Computational Materials}, volume = {8}, year = {2022}, month = {12}, doi = {10.1038/s41524-022-00924-2}, author = {Jangid, Devendra and Brodnik, Neal and Goebel, Michael and Khan, Amil and Majeti, SaiSidharth and Echlin, Mclean and Daly, Samantha and Pollock, Tresa and Manjunath, B.} } @article {1961, title = {Determination of peak ordering in the CrCoNi medium-entropy alloy via nanoindentation}, journal = {Acta Materialia}, volume = {241}, year = {2022}, month = {09}, pages = {118380}, doi = {10.1016/j.actamat.2022.118380}, author = {Zhang, Mingwei and Yu, Qin and Frey, Carolina and Walsh, Flynn and Payne, Madelyn and Kumar, Punit and Liu, Dongye and Pollock, Tresa and Asta, Mark and Ritchie, Robert and Minor, Andrew} } @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 {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 {1991, title = {Scan strategies in EBM-printed IN718 and the physics of bulk 3D microstructure development}, journal = {Materials Characterization}, volume = {190}, year = {2022}, month = {06}, pages = {112043}, doi = {10.1016/j.matchar.2022.112043}, author = {Polonsky, Andrew and Raghavan, Narendran and Echlin, Mclean and Kirka, M. and Dehoff, Ryan and Pollock, Tresa} } @conference {2061, title = {3D Characterization of the Columnar-to-Equiaxed Transition in Additively Manufactured Inconel 718.}, year = {2021}, month = {09}, doi = {10.2172/1886524}, author = {Polonsky, Andrew and Raghavan, Narendran and Echlin, Mclean and Kirka, Michael and Dehoff, Ryan and Pollock, Tresa} } @article {2101, title = {Corrigendum to {\textquotedblleft}Defects and 3D structural inhomogeneity in electron beam additively manufactured Inconel 718{\textquotedblright} [Materials Characterization 143 (2018) 171{\textendash}181]}, journal = {Materials Characterization}, volume = {176}, year = {2021}, month = {06}, pages = {111069}, doi = {10.1016/j.matchar.2021.111069}, author = {Polonsky, Andrew and Echlin, Mclean and Lenthe, William and Dehoff, Ryan and Kirka, M. and Pollock, Tresa} } @article {2111, title = {Damage mechanism identification in composites via machine learning and acoustic emission}, journal = {npj Computational Materials}, volume = {7}, year = {2021}, month = {06}, pages = {95}, doi = {10.1038/s41524-021-00565-x}, author = {Muir, C. and Swaminathan, B. and Almansour, Amjad and Sevener, Kathleen and Smith, C. and Presby, Michael and Kiser, J. and Pollock, T. and Daly, S.} } @article {1661, title = {Influence of plastic deformation on the magnetic properties of Heusler MnAu2Al}, journal = {Phys. Rev. Materials}, volume = {5}, year = {2021}, month = {01/2021}, chapter = {014408}, abstract = {

The Heulser intermetallic\ MnAu2Al\ is shown to undergo a dramatic change in net magnetization in response to plastic deformation. A mechanism is proposed involving antiferromagnetic interactions in the otherwise ferromagnetic compound (when ordered) that arise due to chemical changes at the antiphase boundaries created by the deformation. The coupling between chemical and magnetic order across antiphase boundaries is likely to occur in other ordered magnetic systems and may provide an explanation for otherwise anomalous magnetic behavior across several systems, including other Heusler intermetallics.

}, doi = {https://doi.org/10.1103/PhysRevMaterials.5.014408}, url = {https://journals.aps.org/prmaterials/abstract/10.1103/PhysRevMaterials.5.014408}, author = {Levin, Emily E. and Kitchaev, Daniil A. and Eggeler, Yolita M and Mayer, Justin A. and Behera, Piush and Gianola, Daniel S. and Van der Ven, Anton and Pollock, Tresa M. and Seshadri, Ram} } @article {2126, title = {Interpreting acoustic energy emission in SiC/SiC minicomposites through modeling of fracture surface areas}, journal = {Journal of the European Ceramic Society}, year = {2021}, month = {06}, doi = {10.1016/j.jeurceramsoc.2021.06.030}, author = {Swaminathan, B. and McCarthy, N. and Almansour, Amjad and Sevener, Kathleen and Musaffar, Abed and Pollock, T. and Kiser, J. and Daly, S.} } @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 {2036, title = {A machine learning framework for damage mechanism identification from acoustic emissions in unidirectional SiC/SiC composites}, journal = {npj Computational Materials}, volume = {7}, year = {2021}, month = {12}, doi = {10.1038/s41524-021-00620-7}, author = {Muir, C. and Swaminathan, B. and Fields, K. and Almansour, Amjad and Sevener, Kathleen and Smith, C. and Presby, Michael and Kiser, J. and Pollock, T. and Daly, S.} } @article {2136, title = {Microscale Characterization of Damage Accumulation in CMCs}, journal = {Journal of the European Ceramic Society}, volume = {41}, year = {2021}, month = {05}, pages = {3082-3093}, doi = {10.1016/j.jeurceramsoc.2020.05.077}, author = {Swaminathan, B. and McCarthy, N. and Almansour, Amjad and Sevener, Kathleen and Pollock, T. and Kiser, J. and Daly, S.} } @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 {2116, title = {TriBeam tomography and microstructure evolution in additively manufactured Alnico magnets}, journal = {Materials Today}, volume = {49}, year = {2021}, month = {06}, doi = {10.1016/j.mattod.2021.05.003}, author = {Rottmann, Paul and Polonsky, Andrew and Francis, Toby and Emigh, Megan and Krispin, Michael and Rieger, Gotthard and Echlin, Mclean and Levi, Carlos and Pollock, Tresa} } @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 {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 {1581, title = {Microscale characterization of damage accumulation in CMCs}, journal = {Journal of the European Ceramic Society}, year = {2020}, abstract = {

The developing roles of damage mechanisms in the failure response of SiC/SiC minicomposites was investigated by the characterization of microscale damage accumulation with respect to microstructure. A multi-modal approach combining spatially resolved acoustic emission (AE) with tensile testing in-SEM (scanning electron microscope) was used to simultaneously examine surface (observed in-SEM) and bulk damage (monitored via AE). Strong agreement was shown between the evolving crack density estimated by AE and in-SEM measurements. The following were observed: (i) in-plane matrix content and distribution impacted crack growth; (ii) spatially-distributed matrix cracks generated varying stress-dependent AE; and (iii) certain individual cracks became more probable failure locations due to unique combinations of damage mechanisms that drove their growth. This approach enabled characterizing potential failure determinants and suggests that early damage behavior is related to certain microstructural features (e.g. surface flaws), while subsequent damage behavior is coupled to interactions of local mechanisms evolving with stress.

}, keywords = {Acoustic emission, Ceramic matrix composite, Cracking, Damage initiation, Silicon carbide}, issn = {1873619X}, doi = {10.1016/j.jeurceramsoc.2020.05.077}, url = {https://doi.org/10.1016/j.jeurceramsoc.2020.05.077}, author = {Swaminathan, B. and McCarthy, N. R. and Almansour, A. S. and Sevener, K. and Pollock, T. M. and Kiser, J. D. and Daly, S.} } @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 {1691, title = {Multiplicity of dislocation pathways in a refractory multiprincipal element alloy}, journal = {Science}, volume = {370}, year = {2020}, pages = {95{\textendash}101}, abstract = {

Refractory multiprincipal element alloys (MPEAs) are promising materials to meet the demands of aggressive structural applications, yet require fundamentally different avenues for accommodating plastic deformation in the body-centered cubic (bcc) variants of these alloys. We show a desirable combination of homogeneous plastic deformability and strength in the bcc MPEA MoNbTi, enabled by the rugged atomic environment through which dislocations must navigate. Our observations of dislocation motion and atomistic calculations unveil the unexpected dominance of nonscrew character dislocations and numerous slip planes for dislocation glide. This behavior lends credence to theories that explain the exceptional high temperature strength of similar alloys. Our results advance a defect-aware perspective to alloy design strategies for materials capable of performance across the temperature spectrum.

}, issn = {10959203}, doi = {10.1126/science.aba3722}, author = {Wang, Fulin and Balbus, Glenn H. and Xu, Shuozhi and Su, Yanqing and Shin, Jungho and Rottmann, Paul F. and Knipling, Keith E. and Stinville, Jean Charles and Mills, Leah H. and Senkov, Oleg N. and Beyerlein, Irene J. and Pollock, Tresa M. and Gianola, Daniel S.} } @article {1351, title = {BisQue for 3D Materials Science in the Cloud: Microstructure{\textendash}Property Linkages}, journal = {Integrating Materials and Manufacturing Innovation}, volume = {8}, year = {2019}, pages = {52{\textendash}65}, abstract = {

Accelerating the design and development of new advanced materials is one of the priorities in modern materials science. These efforts are critically dependent on the development of comprehensive materials cyberinfrastructures which enable efficient data storage, management, sharing, and collaboration as well as integration of computational tools that help establish processing\–structure\–property relationships. In this contribution, we present implementation of such computational tools into a cloud-based platform called BisQue (Kvilekval et al., Bioinformatics 26(4):554, 2010). We first describe the current state of BisQue as an open-source platform for multidisciplinary research in the cloud and its potential for 3D materials science. We then demonstrate how new computational tools, primarily aimed at processing\–structure\–property relationships, can be implemented into the system. Specifically, in this work, we develop a module for BisQue that enables microstructure-sensitive predictions of effective yield strength of two-phase materials. Towards this end, we present an implementation of a computationally efficient data-driven model into the BisQue platform. The new module is made available online (web address: https://bisque.ece.ucsb.edu/module_service/Composite_Strength/) and can be used from a web browser without any special software and with minimal computational requirements on the user end. The capabilities of the module for rapid property screening are demonstrated in case studies with two different methodologies based on datasets containing 3D microstructure information from (i) synthetic generation and (ii) sampling large 3D volumes obtained in experiments.

}, keywords = {Cloud-based computing, Homogenization, Materials cyberinfrastructure, Reduced order models}, isbn = {4019201900}, issn = {21939772}, doi = {10.1007/s40192-019-00128-5}, author = {Latypov, Marat I. and Khan, Amil and Lang, Christian A. and Kvilekval, Kris and Polonsky, Andrew T. and Echlin, McLean L.P. and Beyerlein, Irene J. and Manjunath, B. S. and Pollock, Tresa M.} } @article {1361, title = {Three-dimensional Analysis and Reconstruction of Additively Manufactured Materials in the Cloud-Based BisQue Infrastructure}, journal = {Integrating Materials and Manufacturing Innovation}, volume = {8}, year = {2019}, pages = {37{\textendash}51}, abstract = {

A microstructure analytics and 3D reconstruction software package, DREAM.3D, was integrated as a module into a cloud-based platform, BisQue. Parallelization of DREAM.3D module executions and the ability to parameterize pipeline variables over a range of values have led to insights about the grain segmentation misorientation tolerance in TriBeam-collected 3D EBSD datasets of additively manufactured materials with complex anisotropic microstructures. Furthermore, a comparison in grain size measurements was made between standard 2D metallographic slices and 3D measures using BisQue\&$\#$39;s parallelized DREAM.3D module executions. The direction of cloud-based data infrastructure and the prospects for impact in material science are also discussed.

}, keywords = {3D materials science, 3D metal printing, Additive manufacturing, Cloud infrastructure, Microstructure analytics, Tomography}, isbn = {4019201900}, issn = {21939772}, doi = {10.1007/s40192-019-00126-7}, author = {Polonsky, Andrew T. and Lang, Christian A. and Kvilekval, Kristian G. and Latypov, Marat I. and Echlin, McLean L.P. and Manjunath, B. S. and Pollock, Tresa M.} } @article {1471, title = {Application of chord length distributions and principal component analysis for quantification and representation of diverse polycrystalline microstructures}, journal = {Materials Characterization}, volume = {145}, year = {2018}, pages = {671{\textendash}685}, abstract = {

Quantification of mesoscale microstructures of polycrystalline materials is important for a range of practical tasks of materials design and development. The current protocols of quantifying grain size and morphology often rely on microstructure metrics (e.g., mean grain diameter) that overlook important details of the mesostructure. In this work, we present a quantification framework based on directionally resolved chord length distribution and principal component analysis as a means of extracting additional information from 2-D microstructural maps. Towards this end, we first present in detail a method for calculating chord length distribution based on boundary segments available in modern digital datasets (e.g., from microscopy post-processing) and their low-rank representations by principal component analysis. The utility of the proposed framework for capturing grain size, morphology, and their anisotropy for efficient visualization, representation, and specification of polycrystalline microstructures is then demonstrated in case studies on datasets from synthetic generation, experiments (on Ni-base superalloys), and simulations (on steel during recrystallization).

}, keywords = {Chord length distribution, EBSD, Grain size, Microstructure, Principal component analysis}, issn = {10445803}, doi = {10.1016/j.matchar.2018.09.020}, url = {https://doi.org/10.1016/j.matchar.2018.09.020}, author = {Latypov, Marat I. and K{\"u}hbach, Markus and Beyerlein, Irene J. and Stinville, Jean Charles and Toth, Laszlo S. and Pollock, Tresa M. and Kalidindi, Surya R.} } @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 {1326, title = {Defects and 3D structural inhomogeneity in electron beam additively manufactured Inconel 718}, journal = {Materials Characterization}, volume = {143}, year = {2018}, pages = {171{\textendash}181}, abstract = {

Material structure and defects created during additive manufacturing contribute to the variability in mechanical properties of these parts, limiting their use for critical applications. Three-dimensional crystallographic, structural, and chemical information in electron beam melted Inconel 718 was collected from the sub-micron to the millimeter scale using the TriBeam tomography system. The relationship of defects to the surrounding microstructure has been studied in detail. Lack of fusion defects created sharp discontinuities in the grain morphology that extended several build layers beyond the layer where the defect originated. Nitrides and carbides in the size range of 1.25 \μm to 10 \μm were observed throughout the volume, with pronounced nitride clustering. The similarities between solidification in additive manufacturing and traditional manufacturing processes are demonstrated by the comparable size and distribution of carbides measured for industrial-scale samples of 718. Defects created during additive manufacturing cannot be easily remedied via standard post-processing techniques, and will likely diminish the mechanical performance of additively manufactured parts.

}, keywords = {Additive manufacturing, Electron beam melting, Lack of fusion, Microstructure, Tomography}, issn = {10445803}, doi = {10.1016/j.matchar.2018.02.020}, author = {Polonsky, Andrew T. and Echlin, Mclean P. and Lenthe, William C. and Dehoff, Ryan R. and Kirka, Michael M. 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 {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 {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 {1196, title = {On Slip Initiation in Equiaxed Alpha/Beta Ti-6Al-4V}, journal = {Acta Materialia}, volume = {136}, year = {2017}, chapter = {288}, doi = {https://doi.org/10.1016/j.actamat.2017.06.059}, url = {https://www.sciencedirect.com/science/article/pii/S1359645417305360?via\%3Dihub}, author = {Kasemer, M and Echlin, MP and Stinville, JC and Pollock, TM and Dawson, P} } @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 {verma2016microstructure, title = {Microstructure Evolution of Biphasic TiNi1+ x Sn Thermoelectric Materials}, journal = {Metallurgical and Materials Transactions A}, year = {2016}, pages = {1{\textendash}12}, publisher = {Springer US}, author = {Verma, Nisha and Douglas, Jason E and Kr{\"a}mer, Stephan and Pollock, Tresa M and Seshadri, Ram and Levi, Carlos G} } @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 {ardeljan2015study, title = {A study of microstructure-driven strain localizations in two-phase polycrystalline HCP/BCC composites using a multi-scale model}, journal = {International Journal of Plasticity}, volume = {74}, year = {2015}, pages = {35{\textendash}57}, publisher = {Pergamon}, author = {Ardeljan, Milan and Knezevic, Marko and Nizolek, Thomas and Beyerlein, Irene J and Mara, Nathan A and Pollock, Tresa M} } @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} } @conference {suzuki2014oxide, title = {Oxide-assisted crack growth in hold-time low-cycle-fatigue of single-crystal superalloys}, booktitle = {MATEC Web of Conferences}, volume = {14}, year = {2014}, pages = {04004}, publisher = {EDP Sciences}, organization = {EDP Sciences}, author = {Suzuki, Akane and Gao, Yan and Lipkin, Don and Singhal, Anjali and Krug, Matthew and Konitzer, Douglas and Almer, Jonathan and Pollock, Tresa and Bewlay, Bernard} } @article {knezevic2014texture, title = {Texture evolution in two-phase Zr/Nb lamellar composites during accumulative roll bonding}, journal = {International Journal of Plasticity}, volume = {57}, year = {2014}, pages = {16{\textendash}28}, publisher = {Pergamon}, author = {Knezevic, Marko and Nizolek, Thomas and Ardeljan, Milan and Beyerlein, Irene J and Mara, Nathan A and Pollock, Tresa M} } @article {knezevic2013anomalous, title = {Anomalous basal slip activity in zirconium under high-strain deformation}, journal = {Materials Research Letters}, volume = {1}, number = {3}, year = {2013}, pages = {133{\textendash}140}, publisher = {Taylor \& Francis}, author = {Knezevic, Marko and Beyerlein, Irene J and Nizolek, Thomas and Mara, Nathan A and Pollock, Tresa M} } @article {echlin2013ebsd, title = {EBSD Imaging of Femtosecond Laser Ablated Surfaces Using the TriBeam System}, journal = {Microscopy and Microanalysis}, volume = {19}, number = {S2}, year = {2013}, pages = {864{\textendash}865}, publisher = {Cambridge Univ Press}, author = {Echlin, MP and Titus, M and Kraemer, S and Pollock, T} } @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 {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 {adharapurapu2011carburization, title = {Carburization of W-and Re-rich Ni-based alloys in impure helium at 1000{\textdegree} C}, journal = {Corrosion Science}, volume = {53}, number = {1}, year = {2011}, pages = {388{\textendash}398}, publisher = {Elsevier}, author = {Adharapurapu, Raghavendra R and Kumar, Deepak and Zhu, Jun and Pollock, Tresa M} } @article {adharapurapu2011chromia, title = {Chromia-Assisted Decarburization of W-Rich Ni-Based Alloys in Impure Helium at 1273 K (1000{\textdegree} C)}, journal = {Metallurgical and Materials Transactions A}, volume = {42}, number = {5}, year = {2011}, pages = {1229{\textendash}1244}, publisher = {Springer}, author = {Adharapurapu, Raghavendra R and Kumar, Deepak and Zhu, Jun and Torbet, Christopher J and Was, Gary S and Pollock, Tresa M} } @article {mercer2011comparative, title = {A comparative investigation of oxide formation on EQ (Equilibrium) and NiCoCrAlY bond coats under stepped thermal cycling}, journal = {Surface and Coatings Technology}, volume = {205}, number = {8}, year = {2011}, pages = {3066{\textendash}3072}, publisher = {Elsevier}, author = {Mercer, C and Kawagishi, K and Tomimatsu, T and Hovis, D and Pollock, TM} } @article {torralva2011critical, title = {The Critical Role of Shock Melting in Ultrafast Laser Machining}, journal = {Minerals, Metals and Materials Society/AIME, 420 Commonwealth Dr., P. O. Box 430 Warrendale PA 15086 United States.[np]. Feb}, year = {2011}, publisher = {Minerals, Metals and Materials Society/AIME, 420 Commonwealth Dr., P. O. Box 430 Warrendale PA 15086 United States}, author = {Torralva, Ben and Ma, S and Kumar, A and Yalisove, SM and Pollock, TM and Thornton, K} } @article {kumar2011high, title = {High-Temperature Oxidation of Alloy 617 in Helium Containing Part-Per-Million Levels of CO and CO2 as Impurities}, journal = {Metallurgical and Materials Transactions A}, volume = {42}, number = {5}, year = {2011}, pages = {1245{\textendash}1265}, publisher = {Springer}, author = {Kumar, Deepak and Adharapurapu, Raghavendra R and Pollock, Tresa M and Was, Gary S} } @article {kumar2011situ, title = {In situ damage assessment in a cast magnesium alloy during very high cycle fatigue}, journal = {Scripta Materialia}, volume = {64}, number = {1}, year = {2011}, pages = {65{\textendash}68}, publisher = {Elsevier}, author = {Kumar, Anish and Adharapurapu, Raghavendra R and Jones, J Wayne and Pollock, Tresa M} } @article {kumar2011mapping, title = {Mapping of femtosecond laser-induced collateral damage by electron backscatter diffraction}, journal = {Journal of Applied Physics}, volume = {110}, number = {8}, year = {2011}, pages = {083114}, publisher = {AIP Publishing}, author = {Kumar, Anish and Pollock, Tresa M} } @article {suzuki2010crack, title = {Crack progression during sustained-peak low-cycle fatigue in single-crystal Ni-base superalloy Ren{\'e} N5}, journal = {Metallurgical and Materials Transactions A}, volume = {41}, number = {4}, year = {2010}, pages = {947{\textendash}956}, publisher = {Springer US}, author = {Suzuki, A and Gigliotti, MFX and Hazel, BT and Konitzer, DG and Pollock, TM} } @article {kumar2010situ, title = {In situ characterization of fatigue damage evolution in a cast Al alloy via nonlinear ultrasonic measurements}, journal = {Acta Materialia}, volume = {58}, number = {6}, year = {2010}, pages = {2143{\textendash}2154}, publisher = {Pergamon}, author = {Kumar, Anish and Torbet, Christopher J and Pollock, Tresa M and Jones, J Wayne} } @booklet {huang2010mechanical, title = {On Mechanical Properties and Microstructures of TTMP Wrought Mg Alloys}, 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 = {Huang, Jack and Arbel, Tamir and Ligeski, Laura and McCaffrey, Jesse and Kulkarni, Sanjay and Jones, J and Pollock, Tresa and Decker, Raymond and LeBeau, Steve} } @article {kumar2009nonlinear, title = {Nonlinear ultrasonics for in situ damage detection during high frequency fatigue}, journal = {Journal of Applied Physics}, volume = {106}, number = {2}, year = {2009}, pages = {024904}, publisher = {AIP Publishing}, author = {Kumar, Anish and Torbet, Christopher J and Jones, J Wayne and Pollock, Tresa M} } @article {kozar2009strengthening, title = {Strengthening mechanisms in polycrystalline multimodal nickel-base superalloys}, journal = {Metallurgical and Materials Transactions A}, volume = {40}, number = {7}, year = {2009}, pages = {1588{\textendash}1603}, publisher = {Springer}, author = {Kozar, RW and Suzuki, A and Milligan, WW and Schirra, JJ and Savage, MF 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 {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} } @article {kulkarni2007ternary, title = {Ternary diffusion in a RuAl-NiAl couple}, journal = {Journal of Phase Equilibria and Diffusion}, volume = {28}, number = {6}, year = {2007}, pages = {503{\textendash}509}, publisher = {Springer US}, author = {Kulkarni, KN and Tryon, B and Pollock, TM and Dayananda, MA} } @article {elliott2004directional, title = {Directional solidification of large superalloy castings with radiation and liquid-metal cooling: a comparative assessment}, journal = {Metallurgical and Materials Transactions A}, volume = {35}, number = {10}, year = {2004}, pages = {3221{\textendash}3231}, publisher = {Springer-Verlag}, author = {Elliott, AJ and Pollock, TM and Tin, S and King, WT and Huang, S-C and Gigliotti, MFX} } @conference {elliott2003defect, title = {Defect reduction in large superalloy castings by liquid-tin assisted solidification.}, booktitle = {PARSONS 2003: Sixth International Charles Parsons Turbine Conference}, year = {2003}, pages = {649{\textendash}661}, author = {Elliott, AJ and Pollock, TM and Tin, S and King, WT and Huang, S-C and Gigliotti, MFX} } @booklet {king2000nickel, title = {Nickel-based superalloys exhibiting minimal grain defects}, year = {2000}, note = {US Patent 6,096,141}, author = {King, Warren Tan and Pollock, Tresa M and Zemsky, Christine Louise and Murphy, Wendy Howard} } @conference {pollock2000superalloys, title = {Superalloys 2000}, booktitle = {Ninth International Symposium on Superalloys}, year = {2000}, pages = {2000}, author = {Pollock, TM and Kissinger, RD and Bowman, RR and Green, K} } @article {kolluru1998numerical, title = {Numerical modeling of the creep behavior of unidirectional eutectic composites}, journal = {Acta materialia}, volume = {46}, number = {8}, year = {1998}, pages = {2859{\textendash}2876}, publisher = {Elsevier}, author = {Kolluru, Dakshinamurthy V and Pollock, Tresa M} } @conference {pollock1995deformation, title = {DEFORMATION OF NiAl-BASED INTERMETALLICS}, booktitle = {Micromechanics of Advanced Materials: A Symposium in Honor of Professor James CM Li{\textquoteright}s 70th Birthday: Proceedings of a Symposium}, year = {1995}, pages = {205}, publisher = {Minerals, Metals, \& Materials Society}, organization = {Minerals, Metals, \& Materials Society}, author = {Pollock, TM and Kolluru, D} } @article {kitano1994effect, title = {The effect of impurity content on thermally activated deformation in NiAl single crystals}, journal = {Scripta metallurgica et materialia}, volume = {31}, number = {4}, year = {1994}, pages = {397{\textendash}402}, publisher = {Pergamon}, author = {Kitano, K and Pollock, TM and Noebe, RD} } @conference {kitano1993kinetics, title = {The kinetics of low temperature deformation in NiAl single crystals}, booktitle = {Proc first int symp struct intermet, TMS, Warrendale, PA}, year = {1993}, pages = {591{\textendash}599}, author = {Kitano, K and Pollock, TM} }