Yield anomaly in L12 Co3AlxW1−x vis-à-vis Ni3Al

Abstract First principles calculations were performed in Co 3 Al x W 1−x to estimate fault energies, elastic constants and parameters determining the thermodynamic viability and kinetics of yield anomaly. These parameters predict the occurrence of yield anomaly, but only for a limited range of compositions. The driving force for cross-slip resulting in sessile dislocation configurations and cube slip is lower in Co 3 Al x W 1−x than Ni 3 Al due to the less-pronounced anisotropy between antiphase boundary energies on the cube and octahedral planes. Yield anomaly is expected at higher temperatures in Co 3 Al x W 1−x because of the higher activation energy resulting from the higher shear modulus.