First-principles study on the effect of Hf content onmartensitic transformation temperatureof TiNiHf alloy

In this paper a first-principles study of the electronic structure and stability of B2 Ti_1 - xNiHf_x \,(x=0.2, 0.4, 0.6) and B19^\prime Ti_1 - xNiHf_x(x=0, 0.5) alloys is presented. The calculations are performed by the plane-wave pseudopotential method in the framework of the density functional theorywith the generalized gradient approximation. This paper calculates the lattice parameters, density of states, charge density, and heats of formation. The results show that the electronic structure and stability of B2 Ti_1 - xNiHf_x change gradually with Hf content. However, Hf content has little effect on the electronic structure and stability of B19^\prime Ti_1 - xNiHf_x. The mechanism of the effect of Hf content on martensitic transformation temperature of TiNiHf alloys is studied from the electronic structure.