中文摘要：

为了理解NiTi形状记忆合金马氏体相变的机理，基于密度泛函的第一性原理研究了温度和应力对电子结构的稳定性的影响．通过对态密度的分析，发现随着温度的降低和变形的增加，B2相的态密度升高，能级兼并性提高，从而导致结构的稳定性降低，促进相变的发生．

英文摘要：

In order to systematically understand the mechanism of martensitic transformation of NiTi shape-memory alloy, and to study the effect of temperature and stress on the electronic structure, we have carried out first-principles calculations based on the density-functional theory （ DFT）. Analysis of density of states shows that martensitic transformation induces the Fermi face to shift and the density of states near the Fermi face to decrease. With the temperature decreasing and deformation increasing, the density of state of 132 phase and the degree of energy band overlaps increase, thus the stability decrease.