@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 = {<p>
	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, \&lsquo;\&gamma;a\&prime;\&$\#$39; which approximates the bonding environment of an APB better than a previously reported structure, \&lsquo;\&omega;\&$\#$39;. Density functional theory calculations were employed to predict the APB energies from structural energies of \&gamma;a\&prime; and L12 and were validated against estimations from supercell methods for several binary compounds. The implications of the discovery of the \&gamma;a\&prime; are discussed.
</p>
},
	keywords = {Antiphase boundaries, Density functional theory, High-throughput calculations, Planar faults energies, Superalloys},
	issn = {13596462},
	doi = {10.1016/j.scriptamat.2020.02.038},
	url = {https://doi.org/10.1016/j.scriptamat.2020.02.038},
	author = {Vamsi, K. V. and Pollock, Tresa M.}
}
@conference {1601,
	title = {The Yield Strength Anomaly in Co-Ni Design Space},
	booktitle = {Superalloys 2020},
	year = {2020},
	publisher = {Springer International Publishing},
	organization = {Springer International Publishing},
	abstract = {<p>
	A new computational approach to model precipitate compositions and properties in the CoNi-design space for yield strength anomaly prediction is presented. The antiphase boundary (APB) energies on {111} and {010} and the degree of elastic anisotropy are known to influence the yield strength anomaly. APB energies were estimated by a diffuse multi-layer fault (DMLF) model using the structural energies of proximate structures: L12, ca\&prime;, and D023. The elastic moduli were calculated via the energy-strain approach using density functional theory calculations. (Ni1\&minus;xCox)3(Al1\&minus;yWy) was chosen as the model system, and Yoo\&$\#$39;s criterion is evaluated over the entire range ofcompositions to identify regions that exhibit the yield strength anomaly. (Ni0.65Co0.35)3(Al0.5W0.5) has the maximum APB (111) and any two-phase alloy (c + c') in Ni\&ndash;Co\&ndash;Al\&ndash;W system with this precipitate composition might exhibit higher strength upon shearing by a matrix dislocation. ThermoCalc was employed to identify stable L12 regions in (Ni1\&minus;xCox)3(Al1\&minus;yWy). The effect of Co on the yield strength anomaly was investigated experimen- tally in three (Ni1\&minus;xCox)3Al alloys with L12 structure. All three alloys exhibited the yield strength anomaly, validat- ing the computational approach. The addition of Co provides solid solution strengthening to Ni3Al at room temperature; however, this contribution to the overall strength diminished as a function of temperature. CoNi-alloys displayed strengths similar to Ni3Al at elevated temperatures with Co addition resulting in a marginal increase in strength at the peak temperature. The present study elucidates that APB energies from a DMLF model combined with elastic moduli can be employed to predict yield strength anomaly using Yoo\&$\#$39;s criteria.
</p>
},
	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}
}
