J. Mater. Sci. Technol. ›› 2009, Vol. 25 ›› Issue (02): 215-218.
A Comparative Study of Elastic Constants of NiTi and NiAl Alloys from First-Principles Calculations
吕建民;胡青苗;杨锐
- 中科院金属所
A Comparative Study of Elastic Constants of NiTi and NiAl Alloys from First-Principle Calculations
Jianmin Lu†, Qingmiao Hu and Rui Yang
摘要：
To investigate the origin of the strong dependence of martensitic transformation temperature on composition, the elastic properties of both NiTi and NiAl high temperature B2 phases were calculated by a first-principles method, the exact-muffin orbital method within coherent potential approximation. Both in 50~56 at.% Ni of NiTi and in 60~70 at.% Ni of NiAl in which martensitic transformation occurs, non-basal-plane shear modulus c44 is increasing with increasing Ni content, while basal-plane shear modulus c' is decreasing. But the transformation temperature of NiAl increases with increasing Ni content while that of NiTi decreases from experimental observation. Only the softening of c' is experimentally observed in NiAl, and the decrease of c' with increasing Ni content is responsible for the increase of transformation temperature. It demonstrates that besides c', c44 is also involved in martensitic transformation of NiTi and plays a quite important role.