@article {1796, title = {Grain-Scale Stress States in Microtextured Ti64: Implications for Dwell Fatigue}, journal = {Jom}, volume = {74}, year = {2022}, pages = {3709{\textendash}3719}, abstract = {

The room-temperature fatigue life of titanium alloys with a significant alpha phase fraction is substantially reduced when the peak stress is sustained for a few minutes on each stress cycle. Furthermore, these alloys often form microtextured regions during forging which are known to increase the dwell debit; however, the mechanisms for this reduction are still not well understood. In this research, an experimentally collected 3D microstructure of equiaxed Ti-6Al-4V containing microtextured regions is used as input for linear elastic finite element analysis of grain-level stress states relevant to dwell fatigue. The directional strength to stiffness ratio and a metric related to local plane strain are evaluated around the microtextured regions. Strength to stiffness ratios indicate that misoriented grains within hard microtextured regions will begin to yield at macroscopic stress levels below the yield strength, and, under certain loading conditions, they will yield at lower macroscopic stresses than any other location in the microstructure. Under uniaxial tension, boundaries between hard and soft microtextured regions experience some degree of plane strain loading, which may be linked to enhanced load shedding in these areas during dwell fatigue.

}, isbn = {1183702205}, issn = {15431851}, doi = {10.1007/s11837-022-05423-9}, url = {https://doi.org/10.1007/s11837-022-05423-9}, author = {Wendorf, Joe and Dawson, Paul R. and Pollock, Tresa M.} } @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 {1686, title = {Electron backscattered diffraction using a new monolithic direct detector: High resolution and fast acquisition}, journal = {Ultramicroscopy}, volume = {220}, year = {2021}, pages = {113160}, abstract = {

A monolithic active pixel sensor based direct detector that is optimized for the primary beam energies in scanning electron microscopes is implemented for electron back-scattered diffraction (EBSD) applications. The high detection efficiency of the detector and its large array of pixels allow sensitive and accurate detection of Kikuchi bands arising from primary electron beam excitation energies of 4 keV to 28 keV, with the optimal contrast occurring in the range of 8\–16 keV. The diffraction pattern acquisition speed is substantially improved via a sparse sampling mode, resulting from the acquisition of a reduced number of pixels on the detector. Standard inpainting algorithms are implemented to effectively estimate the information in the skipped regions in the acquired diffraction pattern. For EBSD mapping, an acquisition speed as high as 5988 scan points per second is demonstrated, with a tolerable fraction of indexed points and accuracy. The collective capabilities spanning from high angular resolution EBSD patterns to high speed pattern acquisition are achieved on the same detector, facilitating simultaneous detection modalities that enable a multitude of advanced EBSD applications, including lattice strain mapping, structural refinement, low-dose characterization, 3D-EBSD and dynamic in situ EBSD.

}, keywords = {Direct detection, EBSD, Indexing, Inpainting, SEM, Sparse sampling}, issn = {18792723}, doi = {10.1016/j.ultramic.2020.113160}, url = {https://doi.org/10.1016/j.ultramic.2020.113160}, author = {Wang, Fulin and Echlin, Mclean P. and Taylor, Aidan A. and Shin, Jungho and Bammes, Benjamin and Levin, Barnaby D.A. and De Graef, Marc and Pollock, Tresa M. and Gianola, Daniel 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 {1676, title = {Insight into microstructure-sensitive elastic strain concentrations from integrated computational modeling and digital image correlation}, journal = {Scripta Materialia}, volume = {192}, year = {2021}, pages = {78{\textendash}82}, abstract = {

The microstructural origins of highly localized elastic strain concentrations in polycrystalline microstructures under monotonic loading are studied using grain-scale, in situ digital image correlation and crystal plasticity finite element method. It is shown that the locations of exceptionally high elastic strain concentrations in the microstructure depend on particular crystallographic and morphological orientations of grains and less so on crystalline details of their local neighborhood. Based on these results, we discuss how topological and crystallographic features of annealing twin boundaries can increase the likelihood of slip band initiation throughout the microstructure of polycrystalline Ni-base superalloys.

}, keywords = {Elasticity, Micromechanics, Microstructure, Superalloys}, issn = {13596462}, doi = {10.1016/j.scriptamat.2020.10.001}, url = {https://doi.org/10.1016/j.scriptamat.2020.10.001}, author = {Latypov, Marat I. and Stinville, Jean Charles and Mayeur, Jason R. and Hestroffer, Jonathan M. and Pollock, Tresa M. and Beyerlein, Irene J.} } @article {1666, title = {Kink band and shear band localization in anisotropic perfectly plastic solids}, journal = {Journal of the Mechanics and Physics of Solids}, volume = {146}, year = {2021}, pages = {104183}, abstract = {

Shear-driven strain localization has been observed in a wide variety of materials and may take the form of shear bands or kink bands. Based on observations of kink bands in plastically anisotropic metallic nanolaminates and single crystal metals, we posit that, for the specific case of isochoric deformation, the kinematics of kink band formation are indistinguishable from those of plane strain shear band formation. The only distinction between shear bands and kink bands in these systems would then be that kink bands \‘lock up\&$\#$39; at a particular value of material rotation while shear bands may progress to arbitrarily high strains. In order to investigate whether strong material anisotropy is sufficient to arrest shear localization at a geometry that matches the classic kink band geometry, we model the development of a band of simple shear within an anisotropic perfectly plastic material. The resulting analytical model provides the stress state needed to maintain the kinematics of simple shear as a function of material anisotropy, deformation band orientation, and shear strain (or equivalently, material rotation). It is found that plastic anisotropy can promote either kink band or shear band formation depending on the loading orientation. When the deviatoric stress is positive parallel to the plane of anisotropy, shear localization may progress without bound and a shear band is produced. When the deviatoric stress is negative parallel to the plane of anisotropy, shear localization is arrested after a certain material rotation, resulting in a kink band. Examination of the requisite applied stress state during kink band formation provides an explanation for the experimentally-observed \‘lock up\&$\#$39; geometry. Solutions for the band boundary inclination angle are obtained and used to provide bounds on permissible band angles for both shear bands and kink bands.

}, keywords = {Anisotropic material (B), Ideally plastic material (B), Layered material (B), Shear localization}, issn = {00225096}, doi = {10.1016/j.jmps.2020.104183}, url = {https://doi.org/10.1016/j.jmps.2020.104183}, author = {Nizolek, Thomas J. and Pollock, Tresa M. and Mcmeeking, Robert M.} } @article {1671, title = {Temperature dependence of single crystal elastic constants in a CoNi-Base alloy: A new methodology}, journal = {Materials Science and Engineering A}, volume = {803}, year = {2021}, pages = {140507}, abstract = {

A novel experimental setup combining induction heating, contactless (infrared thermometer) temperature measurements, and custom 15 cm length SiC-tipped piezoelectric transducers has been developed to rapidly collect resonant ultrasound spectroscopy (RUS) data from metallic rectangular parallelepiped (RP) specimens heated in air. This setup is used to collect over 70 of the lowest-frequency resonance modes from a single crystal of the novel CoNi-based superalloy SB-CoNi-10+\—an alloy identified for further study due to a promising set of high temperature properties. RUS spectra from room temperature (RT) to 927 \°C (1200 K) along with dilatometry measurements of the thermal expansion behavior are supplied to a robust, open-sourced, Bayesian inference code for simultaneous estimation of: three single crystal elastic constants, three crystal axis misorientation parameters, and a noise parameter. This study is the first application of the Bayesian RUS methodology at elevated temperatures, and the first to characterize SB-CoNi-10+. A monotonic decrease in elastic constants (C11,C12,C44) from (236.4, 150.8, 134.1) GPa to (190.7, 138.1, 95.2) GPa and a 15\% increase in elastic anisotropy from A = 3.131 \→ 3.618 is observed upon heating from RT to 927 \°C, with an increased rate of softening above 600 \°C (873 K).

}, keywords = {Bayesian inference, Elastic constants, High-temperature, Resonant ultrasound spectroscopy, Single crystal, Superalloy}, issn = {09215093}, doi = {10.1016/j.msea.2020.140507}, url = {https://doi.org/10.1016/j.msea.2020.140507}, author = {Goodlet, Brent R. and Murray, Sean P. and Bales, Ben and Rossin, Jeff and Torbet, Chris J. and Pollock, Tresa M.} } @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 {1336, title = {Accelerated discovery of oxidation resistant CoNi-base γ/γ{\textquoteright} alloys with high L12 solvus and low density}, journal = {Materials and Design}, volume = {189}, year = {2020}, pages = {1{\textendash}12}, abstract = {

A systematic and accelerated methodology for alloy design is demonstrated by combining combinatorial synthesis, high-throughput oxide scale characterization, computational density functional theory, and CALPHAD database calculations. By applying this strategy to the senary Co-Ni-W-Al-Cr-Ta material system, a novel \γ/\γ\&$\#$39; alloy exhibiting a superior combination of properties has been identified. Properties include a \γ\&$\#$39; solvus near 1200 \°C, continuous \α-Al2O3 scale formation after 1 h in air at 1100 \°C, and comparable density to 2nd-generation commercial Ni-base superalloys. This novel alloy SB-CoNi-10 has a nominal composition of 39.8Co \– 36.5Ni \– 13.2Al \– 1.0W \– 6.0Cr \– 3.5Ta at.\%, and its properties are compared with other recently studied Co-, CoNi-, and Ni-base \γ/\γ\&$\#$39; alloys.

}, keywords = {Alloy design, Cobalt-base superalloys, Combinatorial synthesis, Oxidation, Superalloys}, issn = {18734197}, doi = {10.1016/j.matdes.2019.108445}, author = {Stewart, Colin A. and Murray, Sean P. and Suzuki, Akane and Pollock, Tresa M. and Levi, Carlos G.} } @inbook {1531, title = {Acquisition of 3D Data for Prediction of Monotonic and Cyclic Properties of Superalloys}, booktitle = {Integrated Computational Materials Engineering (ICME): Advancing Computational and Experimental Methods}, year = {2020}, pages = {1{\textendash}18}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, address = {Cham}, abstract = {

The component design and fatigue life prediction of turbine disk alloys are critically dependent on the thermomechanical properties of the material. The TriBeam microscope provides a pathway to capture large, targeted 3D microstructural data volumes from turbine disk alloys in order to instantiate models that are used to simulate mechanical loading and assess material properties. The TriBeam experiments used to capture the microstructure, the analysis methods, data requirements, and future needs for 3D infrastructure will be discussed.

}, isbn = {978-3-030-40562-5}, doi = {10.1007/978-3-030-40562-5_1}, url = {https://doi.org/10.1007/978-3-030-40562-5_1}, author = {Echlin, Mclean P. and Lenthe, William C. and Stinville, Jean-Charles and Pollock, Tresa M.}, editor = {Ghosh, Somnath and Woodward, Christopher and Przybyla, Craig} } @article {1556, title = {Closing the science gap in 3D metal printing}, journal = {Science}, volume = {368}, year = {2020}, pages = {583{\textendash}584}, abstract = {

Additive manufacturing [three-dimensional (3D) printing] methodologies for high\–melting point metallic materials are being used in the advanced aerospace and biomedical sectors to fabricate high-value and geometrically complex parts in moderate production volumes. One barrier to more widespread applications is the gaps in the understanding of the processes that occur during the layer-by-layer buildup by beam heating and melting of powder or wire layers. For example, the absorption of energy in powder layers that are only a few particles thick is poorly understood. On page 660 of this issue, Khairallah et al. (1) used in situ x-ray synchrotron observations of powder dynamics coupled to thermal and hydrodynamic flow modeling to study energy absorption at the scale of powder particles. The presence of the powder, relative to a flat plate without powder, improves absorptivity at low laser power, but as power approaches 200 W, the details of the powder become far less important.

}, doi = {10.1126/science.abb4938}, author = {Polonsky, Andrew T. and Pollock, Tresa M.} } @article {1651, title = {Expanded dataset of mechanical properties and observed phases of multi-principal element alloys}, journal = {Scientific Data}, volume = {7}, year = {2020}, pages = {1{\textendash}6}, abstract = {

This data article presents a compilation of mechanical properties of 630 multi-principal element alloys\ (MPEAs). Built upon recently published MPEA databases, this article includes updated records from previous reviews (with minor error corrections) along with new data from articles that were published since 2019. The extracted properties include reported composition, processing method, microstructure, density, hardness, yield strength, ultimate tensile strength (or maximum compression strength), elongation (or maximum compression strain), and Young\&$\#$39;s modulus. Additionally, descriptors (e.g. grain size) not included in previous reviews were also extracted for articles that reported them. The database is hosted and continually updated on an open data platform, Citrination. To promote interpretation, some data are graphically presented.

}, issn = {20524463}, doi = {10.1038/s41597-020-00768-9}, author = {Borg, Christopher K.H. and Frey, Carolina and Moh, Jasper and Pollock, Tresa M. and Gorsse, St{\'e}phane and Miracle, Daniel B. and Senkov, Oleg N. and Meredig, Bryce and Saal, James E.} } @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.} } @inbook {1536, title = {Multi-scale Microstructure and Property-Based Statistically Equivalent RVEs for Modeling Nickel-Based Superalloys}, booktitle = {Integrated Computational Materials Engineering (ICME): Advancing Computational and Experimental Methods}, year = {2020}, pages = {55{\textendash}90}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, address = {Cham}, abstract = {

This chapter discusses fundamental aspects of the development of statistically equivalent virtual microstructures (SEVMs) and microstructure and property-based statistically equivalent representative volume elements (M-SERVE and P-SERVE) of the Ni-based superalloy at multiple scales. The two specific scales considered for this development are the subgrain scale of intragranular \γ\thinspace\−\thinspace\γ\textasciiacutex microstructures and the polycrystalline scale of grain ensembles with annealing twins. A comprehensive suite of computational methods that can translate microstructural data in experimental methods to optimally defined representative volumes for effective micromechanical modeling is the objective of this study. The framework involves a sequence of tasks, viz., serial sectioning, image processing, feature extraction, and statistical characterization, followed by micromechanical analysis and convergence tests for statistical functions. A principal motivation behind this paper is to translate high-fidelity microstructural image data into statistics of parametric descriptors in constitutive laws governing material performance.

}, isbn = {978-3-030-40562-5}, doi = {10.1007/978-3-030-40562-5_3}, url = {https://doi.org/10.1007/978-3-030-40562-5_3}, author = {Ghosh, Somnath and Weber, George and Pinz, Maxwell and Bagri, Akbar and Pollock, Tresa M. and Lenthe, Will and Stinville, Jean-Charles and Uchic, Michael D. and Woodward, Christopher}, editor = {Ghosh, Somnath and Woodward, Christopher and Przybyla, Craig} } @article {1331, title = {A new proximate structure for the APB (111) in L12 compounds}, journal = {Scripta Materialia}, volume = {182}, year = {2020}, pages = {38{\textendash}42}, abstract = {

A new approach which involves a diffuse multi-layer fault model coupled with a cluster approach to statistical mechanics (CASM) infrastructure has been developed to identify the proximate structure for the antiphase boundary (APB) on {111} planes in L12. We report a new structure, \‘\γa\′\&$\#$39; which approximates the bonding environment of an APB better than a previously reported structure, \‘\ω\&$\#$39;. Density functional theory calculations were employed to predict the APB energies from structural energies of \γa\′ and L12 and were validated against estimations from supercell methods for several binary compounds. The implications of the discovery of the \γa\′ are discussed.

}, keywords = {Antiphase boundaries, Density functional theory, High-throughput calculations, Planar faults energies, Superalloys}, issn = {13596462}, doi = {10.1016/j.scriptamat.2020.02.038}, url = {https://doi.org/10.1016/j.scriptamat.2020.02.038}, author = {Vamsi, K. V. and Pollock, Tresa M.} } @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 {1566, title = {Serial sectioning in the SEM for three dimensional materials science}, journal = {Current Opinion in Solid State and Materials Science}, year = {2020}, pages = {100817}, abstract = {

Here we explore the range of serial sectioning techniques that have evolved over the past decade, providing a comprehensive toolkit for capturing rich 3D microstructures, chemistries and crystallographic information, with sub-micron resolution at volumes that extend out to mm3 or even cm3. In each case we consider the challenges associated with their application, the volumes they can analyze, the damage to the surface they impart, and their suitability for different materials. In certain cases these warrant hybrid methods, motivating workflows that leverage multiple sectioning modes within the same instrument. Finally, we provide a perspective on their future development, including advances in data collection, segmentation, registration, data fusion, and correlative microscopy. Furthermore, the exploitation of 3D techniques for a better understanding of existing materials, and the design of new ones, is discussed through their use in multiscale modelling, digital twinning, material informatics and machine learning frameworks.

}, keywords = {Biology, Life sciences, Materials science, Scanning electron microscopy, Serial sectioning}, issn = {13590286}, doi = {10.1016/j.cossms.2020.100817}, url = {https://doi.org/10.1016/j.cossms.2020.100817}, author = {Echlin, Mclean P. and Burnett, Timothy L. and Polonsky, Andrew T. and Pollock, Tresa M. and Withers, Philip J.} } @article {1406, title = {Solidification-driven orientation gradients in additively manufactured stainless steel}, journal = {Acta Materialia}, volume = {183}, year = {2020}, pages = {249{\textendash}260}, abstract = {

A sample of 304L stainless steel manufactured by Laser Engineered Net Shaping (LENS) was characterized in 3D using TriBeam tomography. The crystallographic, structural, and chemical properties of the as-deposited microstructure have been studied in detail. 3D characterization reveals complex grain morphologies and large orientation gradients, in excess of 10o, that are not easily interpreted from 2D cross-sections alone. Misorientations were calculated via a methodology that locates the initial location and orientation of grains that grow during the build process. For larger grains, misorientation increased along the direction of solidification. For grains with complex morphologies, K-means clustering in orientation space is demonstrated as a useful approach for determining the initial growth orientation. The gradients in misorientation directly tracked with gradients in chemistry predicted by a Scheil analysis. The accumulation of misorientation is linked to the solutal and thermal solidification path, offering potential design pathways for novel alloys more suited for additive manufacturing.

}, keywords = {Additive manufacturing, Microstructure, Solidification, Tomography, Tribeam}, issn = {13596454}, doi = {10.1016/j.actamat.2019.10.047}, author = {Polonsky, Andrew T. and Lenthe, William C. and Echlin, Mclean P. and Livescu, Veronica and Gray, George T. and Pollock, Tresa M.} } @article {1561, title = {Structural coupling and magnetic tuning in Mn$_{2}$$_{-}$ₓCoₓP magnetocalorics for thermomagnetic power generation}, journal = {APL Materials}, volume = {8}, year = {2020}, pages = {041106}, abstract = {

Promising materials for magnetic refrigeration and thermomagnetic power generation often display strong coupling between magnetism and structure. It has been previously proposed that MnCoP exhibits this strong coupling, contributing to its substantial magnetocaloric effect near TC = 578K. Here, we show from temperature-dependent synchrotron x-ray diffraction that MnCoP displays a discontinuity in the thermal expansion at TC, with spontaneous magnetostriction that is positive in the a direction and negative in the b direction, highlighting the anisotropic nature of the magnetostructural coupling. Varying the Mn:Co ratio of Mn2-xCoxP within the range of 0.6 \≤ x \≤ 1.4 allows the magnetic properties to be tuned. TC decreases as the composition deviates from stoichiometric MnCoP, as does the saturation magnetization. The magnitude of the magnetocaloric effect, |\ΔSM|, decreases as well, due to broadening of the magnetic transition. The large reversible change in magnetization \ΔM accessible over a small temperature range under moderate magnetic fields makes these materials promising for thermomagnetic power generation from waste heat.

}, issn = {2166532X}, doi = {10.1063/1.5142000}, url = {https://doi.org/10.1063/1.5142000}, author = {Levin, Emily E. and Bocarsly, Joshua D. and Grebenkemper, Jason H. and Issa, Ramsey and Wilson, Stephen D. and Pollock, Tresa M. and Seshadri, Ram} } @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} } @article {1401, title = {Three-dimensional maps of geometrically necessary dislocation densities in additively manufactured Ni-based superalloy IN718}, journal = {International Journal of Plasticity}, year = {2020}, pages = {102709}, keywords = {Dislocations, Metallic material, Microstructures, Polycrystalline material, Three-dimensional electron backscatter diffraction}, issn = {0749-6419}, doi = {10.1016/j.ijplas.2020.102709}, url = {https://doi.org/10.1016/j.ijplas.2020.102709}, author = {Witzen, Wyatt A. and Polonsky, Andrew T. and Pollock, Tresa M. and Beyerlein, Irene J.} } @article {1586, title = {Twin related domain networks in Ren{\'e} 88DT}, journal = {Materials Characterization}, volume = {165}, year = {2020}, pages = {110365}, abstract = {

Annealing twins in wrought fcc materials have historically been characterized using simple 2D measures including morphology and volume fraction. Accurately describing twin related domain microstructure requires accounting for their complex 3D structure. A large microstructural volume of a nickel-base alloy Ren\é 88DT has been collected using TriBeam tomography for full characterization of a large number of complete twin related domains. A network based approach enables visualization of twin domain structures. Metrics adapted from graph theory enable the first quantitative 3D microstructure descriptions. The implications for fatigue properties in twinned nickel-base alloys are discussed.

}, keywords = {3D EBSD, Annealing twin boundaries, Graph theory, Nickel-base superalloy, Recrystallization, Tribeam, Twins}, issn = {10445803}, doi = {10.1016/j.matchar.2020.110365}, url = {https://doi.org/10.1016/j.matchar.2020.110365}, author = {Lenthe, William C. and Echlin, Mclean P. and Stinville, Jean C. and De Graef, Marc and Pollock, Tresa M.} } @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 {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 {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 {1396, title = {Creep resistance of bulk copper{\textendash}niobium composites: An inverse effect of multilayer length scale}, journal = {Acta Materialia}, volume = {176}, year = {2019}, pages = {189{\textendash}198}, abstract = {

Metallic multilayer systems show promising performance in extreme environments, with high stability of bi-metal interfaces down to nanometer length scales. The creep behavior of bulk, accumulative roll bonded (ARB) Copper\–Niobium (Cu\–Nb) composites has been studied at 400 \°C as a function of layer thickness, ranging from 2 \μm to 65 nm. Similar to single phase metallic systems, three regimes are observed during creep: transient, steady-state and tertiary. The mechanism controlling minimum creep rate for all conditions tested has a strong dependence on stress, consistent with dislocation-dominated creep. Unlike the conventional effect of grain size on creep resistance, this study reveals that decreasing length scale increases creep resistance.

}, keywords = {Creep, Cu-Nb, Length scale, Multilayer}, issn = {13596454}, doi = {10.1016/j.actamat.2019.06.029}, url = {https://doi.org/10.1016/j.actamat.2019.06.029}, author = {Avallone, Jaclyn T. and Nizolek, Thomas J. and Bales, Benjamin B. 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 {1371, title = {The evolving landscape for alloy design}, journal = {MRS Bulletin}, volume = {44}, year = {2019}, pages = {238{\textendash}246}, abstract = {

The discovery, design, and development of new alloys have long been critical elements of advanced engineering systems. Challenged by their chemical and structural complexity, this design process is, however, often too slow. This article highlights progress in theory, computation, data, and advanced experimental techniques that are advancing our capabilities for rapid discovery and design of new multicomponent alloys. Applied across the length scales, these new capabilities support exploration across broad composition spaces; examples of new materials and associated advances in the understanding of underlying thermochemical and thermomechanical phenomena are presented. We highlight current challenges, gaps, and specific areas that, if further developed, could have future high payoff.

}, keywords = {alloys, crystallographic structure, electronic structure, phase equilibria, simulation}, issn = {08837694}, doi = {10.1557/mrs.2019.69}, author = {Pollock, Tresa M. and Van der Ven, Anton} } @article {1381, title = {A model for high temperature deformation of nanolaminate Cu-Nb composites}, journal = {Materials Science and Engineering A}, volume = {761}, year = {2019}, pages = {138016}, abstract = {

Nanolaminate composites with layer thicknesses down to 65 nm display conventional 3 stage creep behavior with creep resistance increasing as layer thickness decreases. A model for the time dependent high temperature deformation response of Cu-Nb composites is developed, and compared to creep tests performed on multilayers fabricated via accumulative roll bonding (ARB). The model assumes a continuous laminate structure of 50\% Cu and 50\% Nb in which deformation is controlled by stage II creep for the copper (\ε˙cr=A\σn) and plasticity in Nb. Regimes in which composite steady-state creep at constant stress can be achieved are identified. The modeling illustrates that strain-hardening in the niobium plays a critical role in the transient response of the multilayer, which can dominate the creep lifetime. The combination of experiments and models strongly suggest that dislocation climb mechanisms in the copper control the time-response at 400 oC for all layer thicknesses tested.

}, keywords = {Creep model, Cu-Nb, Multilayer composite, Strain hardening}, issn = {09215093}, doi = {10.1016/j.msea.2019.06.026}, url = {https://doi.org/10.1016/j.msea.2019.06.026}, author = {Avallone, Jaclyn T. and Nizolek, Thomas J. and Pollock, Tresa M. and Begley, Matthew R.} } @article {1391, title = {Oxidation Behavior Across Composition Space Relevant to Co-based γ/γ' Alloys}, journal = {Metallurgical and Materials Transactions A}, volume = {50}, year = {2019}, pages = {5445{\textendash}5458}, issn = {1073-5623}, doi = {10.1007/s11661-019-05413-8}, url = {https://doi.org/10.1007/s11661-019-05413-8}, author = {Stewart, Colin A. and Suzuki, Akane and Rhein, Robert K. and Pollock, Tresa M. and Levi, Carlos G.} } @article {1376, title = {Protocols for High Temperature Assisted-Microwave Preparation of Inorganic Compounds}, journal = {Chemistry of Materials}, volume = {31}, year = {2019}, pages = {7151{\textendash}7159}, abstract = {

Assisted-microwave heating involves the use of a susceptor to initially heat up reactants in a microwave reaction. Once hot, the reactants themselves become directly susceptible to microwave heating and interdiffuse to form products. Assisted-microwave methods are appealing for a wide variety of high temperature solid-state reactions, reaching reaction temperatures of 1500 \°C and more. Among the many advantages are that the direct volumetric heating associated with microwaves allows for rapid reaction times while employing significantly less energy than conventional furnace-based preparation. Shorter reaction times and selective heating permit volatile reactants to be incorporated stoichiometrically in the product. Undesirable reactions with containers or enclosures are also minimized. The morphology of powders obtained through microwave reactions are also more uniform and comprise smaller particles than obtained conventionally. This Methods/Protocols article is presented as a user manual for carrying out assisted-microwave preparation of bulk complex oxides in air or reducing atmospheres and sol-gel based processing of complex oxides, air sensitive intermetallics, and transition metal chalcogenides.

}, issn = {15205002}, doi = {10.1021/acs.chemmater.9b02594}, author = {Levin, Emily E. and Grebenkemper, Jason H. and Pollock, Tresa M. and Seshadri, Ram} } @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 {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 {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 {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 {1426, title = {Bayesian inference of elastic properties with resonant ultrasound spectroscopy}, journal = {The Journal of the Acoustical Society of America}, volume = {143}, year = {2018}, pages = {71{\textendash}83}, abstract = {

\© 2018 Acoustical Society of America. Bayesian modeling and Hamiltonian Monte Carlo (HMC) are utilized to formulate a robust algorithm capable of simultaneously estimating anisotropic elastic properties and crystallographic orientation of a specimen from a list of measured resonance frequencies collected via Resonance Ultrasound Spectroscopy (RUS). Unlike typical optimization procedures which yield point estimates of the unknown parameters, computing a Bayesian posterior yields probability distributions for the unknown parameters, and HMC is an efficient way to compute this posterior. The algorithms described are demonstrated on RUS data collected from two parallelepiped specimens of structural metal alloys. First, the elastic constants for a specimen of fine-grain polycrystalline Ti-6Al-4 V with random crystallographic texture and isotropic elastic symmetry are estimated. Second, the elastic constants and crystallographic orientation for a single crystal Ni-based superalloy CMSX-4 specimen are accurately determined, using only measurements of the specimen geometry, mass, and resonance frequencies. The unique contributions of this paper are as follows: the application of HMC for sampling the Bayesian posterior of a probabilistic RUS model, and the procedure for simultaneous estimation of elastic constants and lattice-specimen misorientation. Compared to previous approaches these algorithms demonstrate superior convergence behavior, particularly when the initial parameterization is unknown, and enable substantially simplified experimental procedures.

}, issn = {0001-4966}, doi = {10.1121/1.5017840}, author = {Bales, Ben and Petzold, Linda and Goodlet, Brent R. and Lenthe, William C. 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 {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 {1166, title = {Discrete dislocation plasticity analysis of the high-temperature cyclic response of composites}, journal = {Materials Science and Engineering: A}, volume = {712}, year = {2018}, pages = {714{\textendash}719}, doi = {10.1016/j.msea.2017.12.034}, author = {Shishvan, Siamak S. and Mcmeeking, Robert M. and Pollock, Tresa M. and Deshpande, Vikram S.} } @article {1421, title = {Enhancing thermoelectric properties through control of Nickel Interstitials and phase separation in Heusler/Half-Heusler TiNi1.1Sn composites}, journal = {Materials}, volume = {11}, year = {2018}, pages = {1{\textendash}12}, abstract = {

Thermoelectric devices, which allow direct conversion of heat into electrical energy, require materials with improved figures of merit (zT) in order to ensure widespread adoption. Several techniques have been proposed to increase the zT of known thermoelectric materials through the reduction of thermal conductivity, including heavy atom substitution, grain size reduction and inclusion of a semicoherent second phase. The goal in these approaches is to reduce thermal conductivity through phonon scattering without modifying the electronic properties. In this work, we demonstrate that Ni interstitials in the half-Heusler thermoelectric TiNiSn can be created and controlled in order to improve physical properties. Ni interstitials in TiNi1.1Sn are not thermodynamically stable and, instead, are kinetically trapped using appropriate heat treatments. The Ni interstitials, which act as point defect phonon scattering centers and modify the electronic states near the Fermi level, result in reduced thermal conductivity and enhance the Seebeck coefficient. The best materials tested here, created from controlled heat treatments of TiNi1.1Sn samples, display zT = 0.26 at 300 K, the largest value reported for compounds in the Ti-Ni-Sn family.

}, keywords = {Heusler, Phonon scattering, Point defect, Thermoelectric, TiNi2Sn, TiNiSn}, issn = {19961944}, doi = {10.3390/ma11060903}, author = {Levin, Emily E. and Long, Francesca and Douglas, Jason E. and Buffon, Malinda L.C. and Lamontagne, Leo K. and Pollock, Tresa M. and Seshadri, Ram} } @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 {1486, title = {Femtosecond laser rejuvenation of nanocrystalline metals}, journal = {Acta Materialia}, volume = {156}, year = {2018}, pages = {183{\textendash}195}, abstract = {

Nanocrystalline metals are distinct from traditional engineering materials due to their high concentration of grain boundaries and corresponding structural disorder at grain boundaries. The effect of local disorder in nanocrystalline materials manifests in ways reminiscent of fully amorphous materials, such as mesoscale shear localization and pressure-dependent yielding, owing to the high concentration of grain boundaries and their predominance in governing plasticity. Relaxation processes in nanocrystalline materials that facilitate reconfigurations of grain boundaries and lower their energy, such as low temperature annealing, have been shown to enhance mechanical strength. However, processes that raise the energy of a nanocrystalline metal have not been observed, limiting the tunability of properties and the prospect for suppressing shear localization. Here, we use femtosecond laser processing as a unique non-equilibrium process that can generate complex stress states due to ultrafast electronic excitation and subsequent relaxation events. Experiments on nanocrystalline Al-O and Cu-Zr alloys indicate that sub-ablation femtosecond laser pulses cause up to an 87\% reduction in hardness with no change in grain size, which can be ascribed to grain boundary-mediated processes. Parallels between our results and rejuvenation processes in glassy systems will be discussed in the context of controlling metastable structural configurations through novel processing routes.

}, keywords = {Femtosecond lasers, Grain boundaries, Nanocrystalline, Rejuvenation}, issn = {13596454}, doi = {10.1016/j.actamat.2018.06.027}, url = {https://doi.org/10.1016/j.actamat.2018.06.027}, author = {Balbus, Glenn H. and Echlin, Mclean P. and Grigorian, Charlette M. and Rupert, Timothy J. and Pollock, Tresa M. and Gianola, Daniel S.} } @article {1451, title = {Grain size effects on NiTi shape memory alloy fatigue crack growth}, journal = {Journal of Materials Research}, volume = {33}, year = {2018}, pages = {91{\textendash}107}, abstract = {

Fatigue cracking in polycrystalline NiTi was investigated using a multiscale experimental framework for average grain sizes (GS) from 10 to 1500 nm for the first time. Macroscopic fatigue crack growth rates, measured by optical digital image correlation, were connected to microscopic crack opening and closing displacements, measured by scanning electron microscope DIC (SEM-DIC) using a high-precision external SEM scan controller. Among all grain sizes, the 1500 nm GS sample exhibited the slowest crack growth rate at the macroscale, and the largest crack opening level (stress intensity at first crack opening) and minimum crack opening displacements at the microscale. Smaller GS samples (10, 18, 42, and 80 nm) exhibited nonmonotonic trends in their fatigue performance, yet the correlation was strong between macroscale and microscale behaviors for each GS. The samples that exhibited the fastest crack growth rates (42 and 80 nm GS) showed a small crack opening level and the largest crack opening displacements. The irregular trends in fatigue performance across the nanocrystalline GS samples were consistent with nonmonotonic values in the elastic modulus reported previously, both of which may be related to the presence of residual martensite only evident in the small GS samples (10 and 18 nm).

}, keywords = {fatigue, nanostructure, scanning electron microscopy (SEM)}, issn = {20445326}, doi = {10.1557/jmr.2017.395}, author = {Lepage, William S. and Ahadi, Aslan and Lenthe, William C. and Sun, Qing Ping and Pollock, Tresa M. and Shaw, John A. and Daly, Samantha H.} } @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 {1321, title = {Rapid Assessment of Oxidation Behavior in Co-Based γ/γ' Alloys}, journal = {Oxidation of Metals}, volume = {90}, year = {2018}, pages = {485{\textendash}498}, keywords = {Cobalt-base superalloys, Combinatorial synthesis, Oxidation, Photostimulated luminescence spectroscopy}, isbn = {0030-770X}, issn = {0030770X}, doi = {10.1007/s11085-018-9849-2}, url = {https://doi.org/10.1007/s11085-018-9849-2}, author = {Stewart, Colin A. and Suzuki, Akane and Pollock, Tresa M. and Levi, Carlos G.} } @article {1211, title = {3D printing of high-strength aluminium alloys}, journal = {Nature}, volume = {549}, year = {2017}, pages = {365{\textendash}369}, doi = {10.1038/nature23894}, author = {Martin, John H. and Yahata, Brennan D. and Hundley, Jacob M. and Mayer, Justin A. and Schaedler, Tobias A. and Pollock, Tresa M.} } @article {1206, title = {Discrete dislocation plasticity analysis of the effect of interfacial diffusion on the creep response of Ni single-crystal superalloys}, journal = {Acta Materialia}, volume = {135}, year = {2017}, pages = {188{\textendash}200}, doi = {10.1016/j.actamat.2017.06.026}, author = {Shishvan, Siamak S. and Mcmeeking, Robert M. and Pollock, Tresa M. and Deshpande, Vikram S.} } @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 {1261, title = {Interfacial diffusion in high-temperature deformation of composites: A discrete dislocation plasticity investigation}, journal = {Journal of the Mechanics and Physics of Solids}, volume = {98}, year = {2017}, pages = {330{\textendash}349}, doi = {10.1016/j.jmps.2016.09.002}, author = {Shishvan, Siamak S. and Pollock, Tresa M. and Mcmeeking, Robert M. and Deshpande, Vikram S.} } @article {1256, title = {Modelling the elastic properties of bi-continuous composite microstructures captured with TriBeam serial-sectioning}, journal = {Computational Materials Science}, volume = {131}, year = {2017}, pages = {187{\textendash}195}, doi = {10.1016/j.commatsci.2017.01.026}, author = {Mignone, Paul J. and Echlin, Mclean P. and Pollock, Tresa M. and Finlayson, Trevor R. and Riley, Daniel P. and Sesso, Mitchell L. and Franks, George V.} } @article {1226, title = {Oxygen evolution on Fe-doped NiO electrocatalysts deposited via microplasma}, journal = {Nanoscale}, volume = {9}, year = {2017}, pages = {15070{\textendash}15082}, doi = {10.1039/c7nr04302c}, author = {Pebley, Andrew C. and Decolvenaere, Elizabeth and Pollock, Tresa M. and Gordon, Michael J.} } @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 {1251, title = {A robust method to characterize rumpling in high-strength bond coats}, journal = {Surface and Coatings Technology}, volume = {317}, year = {2017}, pages = {148{\textendash}157}, doi = {10.1016/j.surfcoat.2017.03.054}, author = {Jorgensen, David J. and Jackson, R. Wesley and Pollock, Tresa M.} } @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 {1186, title = {Tuning the magnetocaloric response in half-Heusler/Heusler MnNi1 xSb solid solutions}, journal = {Physical Review Materials}, volume = {1}, year = {2017}, doi = {10.1103/physrevmaterials.1.075003}, author = {Levin, Emily E. and Bocarsly, Joshua D. and Wyckoff, Kira E. and Pollock, Tresa M. and Seshadri, Ram} }