Yield anomaly in L1₂ Co₃Al_xW_1−x vis-à-vis Ni₃Al

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• 作者：K.V. Vamsi ; S. Karthikeyan ; ^{karthik@materials.iisc.ernet.in}
• 关键词：Planar fault energy ; Yield anomaly ; Co-base superalloys ; Elastic constants ; First principles calculations
• 刊名：Scripta Materialia
• 出版年：2017
• 出版时间：15 March 2017
• 年：2017
• 卷：130
• 期：Complete
• 页码：269-273
• 全文大小：487 K
• 卷排序：130

文摘

First principles calculations were performed in Co3AlxW1−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 Co3AlxW1−x than Ni3Al due to the less-pronounced anisotropy between antiphase boundary energies on the cube and octahedral planes. Yield anomaly is expected at higher temperatures in Co3AlxW1−x because of the higher activation energy resulting from the higher shear modulus.