[SY-E8] Symposium E-8

[SY-E8] Ab initio investigation on the stacking fault energy and the c/a ratio in hexagonal metals and alloys

^○Gang Zhou, Hao Wang, Dong sheng Xu, Rui Yang (Institute of Metal Research, Chinese Academy of Sciences, China)

For structural materials with hexagonal close-packed structures, the stacking fault energy and the ratio of c/a are key factors which have strong correlation with many properties, such as the critical shear stress of dislocations and deformation twinning. We thus employed high-throughput ab initio calculations to investigate the stacking fault energy and the c/a ratio in hexagonal metals, Mg, Ti, Zr, Be and Zn, as well as in alloyed Mg and Ti. The result indicates that the ratio of the unstable stacking fault energy on the prism plane over that on the basal plane, γ^p/γ^b, is primarily relevant to the c/a ratio. In Be, Mg and Zn, γ^p/γ^b increases with c/a leading to increasing preference of basal slip, whereas in Ti and Zr, γ^p/γ^b changes unperceivably with c/a leading to the preference of prism slip. In alloyed Mg and Ti, alloying varies both the stacking fault energy and the c/a ratio and certain alloying elements significantly affect -slip preference in Mg, while alloying exhibits negligible influence on -slip preference in hexagonal Ti.