@article {2211, title = {Rapid Screening of Single Phase Refractory Alloys Under Laser Melting Conditions}, journal = {Materials \& Design}, year = {2024}, pages = {112726}, abstract = {

Refractory alloys can be difficult to fabricate by laser-based manufacturing methods due to their high melting temperatures, high interstitial solubility, and propensity for low temperature brittleness. Laser-based processes, such as welding and additive manufacturing (AM), yield similar populations of defects, including microsegregation and solidification and solid-state cracking. Given the extreme challenges and cost associated with the production of refractory powders, this research aimed to develop a rapid screening methodology that combines predictive defect formation metrics with single track melting experiments. A flexible single laser track melting platform was designed to perform screening experiments on conventional and multi-principal element refractory alloys across a wide range of laser energy inputs. The platform was employed to investigate laser melting on solid substrates, or on a substrate with a single layer of powder feedstock, and is demonstrated with the highly fabricable Nb-base alloy C103. Preliminary investigations are performed on refractory multi-principal element alloys in the Hf-Mo-Nb-Ta-Ti family, and significant differences in cracking resistance and solidification morphology are observed. Implications for future alloy design and processing strategies for defect-resistant refractory alloys for AM are discussed.

}, keywords = {Additive manufacturing, high entropy alloy, multi-principal element alloy, refractory alloys, solid-state cracking, solidification cracking}, issn = {0264-1275}, doi = {https://doi.org/10.1016/j.matdes.2024.112726}, url = {https://www.sciencedirect.com/science/article/pii/S0264127524000984}, author = {Kaitlyn M. Mullin and Carolina Frey and James Lamb and Sophia K. Wu and McLean P. Echlin and Tresa M. Pollock} } @article {2046, title = {Recent Developments in Femtosecond Laser-Enabled TriBeam Systems}, journal = {JOM}, volume = {73}, year = {2021}, month = {11}, pages = {1-12}, doi = {10.1007/s11837-021-04919-0}, author = {Echlin, Mclean and Polonsky, Andrew and Lamb, James and Geurts, Remco and Randolph, Steven and Botman, Aurelien and Pollock, Tresa} } @article {2151, title = {Rejuvenation of Directionally Solidified and Single-Crystal Nickel-Base Superalloys}, journal = {Metallurgical and Materials Transactions A}, volume = {52}, year = {2021}, month = {03}, doi = {10.1007/s11661-021-06150-7}, author = {Rettberg, Luke and Callahan, P. and Goodlet, Brent and Pollock, T.} } @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 {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 {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 {miller2016recrystallization, title = {Recrystallization and the Development of Abnormally Large Grains After Small Strain Deformation in a Polycrystalline Nickel-Based Superalloy}, journal = {Metallurgical and Materials Transactions A}, volume = {47}, number = {4}, year = {2016}, pages = {1566{\textendash}1574}, publisher = {Springer US}, author = {Miller, Victoria M and Johnson, Anthony E and Torbet, Chris J and Pollock, Tresa M} } @conference {biedermann2015resonance, title = {Resonance ultrasound spectroscopy forward modeling and inverse characterization of nickel-based superalloys}, booktitle = {41ST ANNUAL REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION: Volume 34}, volume = {1650}, number = {1}, year = {2015}, pages = {835{\textendash}844}, publisher = {AIP Publishing}, organization = {AIP Publishing}, author = {Biedermann, Eric and Jauriqui, Leanne and Aldrin, John C and Goodlet, Brent and Pollock, Tresa and Torbet, Chris and Mazdiyasni, Siamack} } @article {rhein2015role, title = {Role of vibrational and configurational excitations in stabilizing the L 1 2 structure in Co-rich Co-Al-W alloys}, journal = {Physical Review B}, volume = {92}, number = {17}, year = {2015}, pages = {174117}, publisher = {American Physical Society}, author = {Rhein, Robert K and Dodge, Philip C and Chen, Min-Hua and Titus, Michael S and Pollock, Tresa M and Van der Ven, Anton} } @article {miller2013recrystallization, title = {Recrystallization Behavior of a MgAlCa Alloy during Thermomechanical Processing and Subsequent Heat Treatment}, journal = {Magnesium Technology 2013}, year = {2013}, pages = {203{\textendash}209}, publisher = {Wiley Online Library}, author = {Miller, VM and Pollock, TM} } @article {birkel2012rapid, title = {rapid microwave preparation of thermoelectric TiNiSn and TiCoSb half-heusler compounds}, journal = {Chemistry of Materials}, volume = {24}, number = {13}, year = {2012}, pages = {2558{\textendash}2565}, publisher = {American Chemical Society}, author = {Birkel, Christina S and Zeier, Wolfgang G and Douglas, Jason E and Lettiere, Bethany R and Mills, Carolyn E and Seward, Gareth and Birkel, Alexander and Snedaker, Matthew L and Zhang, Yichi and Snyder, G Jeffrey and others} } @article {rettberg2012rejuvenation, title = {Rejuvenation of Nickel-Based Superalloys GTD444 (DS) and Ren{\'e} N5 (SX)}, journal = {Superalloys 2012}, year = {2012}, pages = {341{\textendash}349}, publisher = {John Wiley \& Sons, Inc.}, author = {Rettberg, LH and Tsunekane, M and Pollock, TM} } @booklet {brundidge2010real, title = {Real Time Synchrotron Radiography of High Temperature High Cycle Fatigue Crack Growth in Single-Crystal Nickel-Base Superalloys}, howpublished = {Minerals, Metals and Materials Society/AIME, 420 Commonwealth Dr., P. O. Box 430 Warrendale PA 15086 USA.[np]. 14-18 Feb}, year = {2010}, publisher = {Minerals, Metals and Materials Society/AIME, 420 Commonwealth Dr., P. O. Box 430 Warrendale PA 15086 USA}, author = {Brundidge, Clinique L and Husseini, Naji and Hanson, Erik and Torbet, Chris and Clarke, Roy and Jones, JWayne and Pollock, Tresa} } @article {tryon2006ruthenium, title = {Ruthenium-containing bond coats for thermal barrier coating systems}, journal = {JoM}, volume = {58}, number = {1}, year = {2006}, pages = {53{\textendash}59}, publisher = {Springer}, author = {Tryon, B and Cao, F and Murphy, KS and Levi, CG and Pollock, TM} } @article {feng2004re, title = {The Re (Ru)-rich $δ$-phase in Ru-containing superalloys}, journal = {Materials Science and Engineering: A}, volume = {373}, number = {1}, year = {2004}, pages = {239{\textendash}249}, publisher = {Elsevier}, author = {Feng, Q and Nandy, TK and Pollock, TM} } @article {smith2001role, title = {The role of impact damage and fatigue strength reduction in gamma titanium aluminide alloys}, journal = {Structural Intermetallics}, year = {2001}, pages = {259{\textendash}268}, author = {Smith, R and Harding, T and Jones, JW and Steif, P and Pollock, TM} } @article {harding1999room, title = {Room temperature fatigue response of $\gamma$-TiAl to impact damage}, journal = {Scripta materialia}, volume = {40}, number = {4}, year = {1999}, pages = {445{\textendash}449}, publisher = {Pergamon}, author = {Harding, Trevor S and Jones, J Wayne and Steif, PS and Pollock, TM} } @article {eow1998rate, title = {Rate sensitivities for low temperature deformation in ruthenium aluminide alloys}, journal = {Scripta materialia}, volume = {38}, number = {7}, year = {1998}, pages = {1065{\textendash}1069}, publisher = {Pergamon}, author = {Eow, K and Lu, D and Pollock, TM} } @article {walston1996renfi, title = {RENfi N6: THIRD GENERATION SINGLE CRYSTAL SUPERALLOY}, year = {1996}, author = {Walston, WS and O{\textquoteright}hara, KS and Ross, EW and Pollock, TM and Murphy, WH} } @article {pollock1992role, title = {The Role of Creep Deformation in Directional Coarsening of gamma{\textquoteright} in Nickel-Base Single Crystals}, journal = {Modeling of Coarsening and Grain Growth}, year = {1992}, pages = {35{\textendash}44}, author = {Pollock, TM and Argon, AS} }