Molecular dynamics (MD) simulations were carried out to study the bulk polycrystalline properties of NiTi. Thermally driven phase transitions of NiTi between martensite and austenitewere simulated using single crystalline simulation domains. With external stress boundary conditions, MD simulation successfully predicted experimentally observed phase transformation temperatures of bulk polycrystalline. Elastic characteristics of NiTi martensite were simulated using polycrystalline simulation domains that consist of realistic disorientations and grain boundary structures. The existence of grain disorientation and grain boundary lowered the potential energy of the simulation domain, which led to more realistic elastic modulus prediction. Analysis of simulation domains that predicted realistic bulk polycrystalline properties showed that the major difference between single crystalline and polycrystalline structures is atomic stress distribution.

中文翻译：

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多晶镍钛块体特性的分子动力学研究

进行分子动力学 (MD) 模拟以研究 NiTi 的块状多晶特性。NiTi 在马氏体和奥氏体之间的热驱动相变使用单晶模拟域进行模拟。借助外部应力边界条件，MD 模拟成功地预测了实验观察到的块状多晶的相变温度。NiTi 马氏体的弹性特性使用多晶模拟域进行模拟，该域由真实的定向障碍和晶界结构组成。晶粒无取向和晶界的存在降低了模拟域的势能，从而导致更真实的弹性模量预测。