EAMポテンシャルによるNi-Al合金における形状記憶効果の分子動力学シミュレーション

抄録

Molecular dynamics simulations on the shape memory effect are carried out by using the EAM potential for Ni-Al alloy. As a preliminary calculation, the stable crystal structures are investigated, so that both bcc and martensite phases are obtained and the temperature-dependent transformation can occur. As a result, it is revealed that 60-70% Ni models show the martensite structure at low temperature, and bcc at high temperature, and the transformation temperature depends on the Ni content. In order to simulate the shape-memory behavior, a series of loading, unloading, heating, and cooling conditions is imposed for 68% Ni model. In the loading process, the model is deformed by the motion of variant boundaries, and a large deformation is observed. The deformation does not disappear even the model is unloaded. However, the model recovers the original shape when it bears the heat treatment process incorporating the phase transformation to bcc structure.