TiAl合金基体表面Ti薄膜在升温过程中结构变化的分子动力学模拟

MOLECULAR DYNAMICS SIMULATION OF STRUCTURAL CHANGES IN Ti FILMS COVERING OVER THE TiAl ALLOY SUBSTRATE DURING HEATING

应用分子动力学方法计算了TiAl合金基体表面的Ti薄膜在温度升高过程中的结构变化,计算中所用的势由嵌入原子模型得到,TiAl合金基体表面的结构分为Ti和Al原子层2种情况.通过对键类型、原子均方位移、原子密度分布和分层局域结构内的原子排布等随温度的变化进行分析,发现在升温过程中由于原子之间位置的交换,薄膜结构分阶段发生变化;基体表层分别为Ti或Al原子层时,Ti薄膜内的原子排列结构呈现出不同的变化形式.

Structural changes in Ti films covering over Ti or Al atomic layer on the TiAl substrate during heating were investigated by molecular dynamics simulations within the framework of embedded atom method（EAM）.On the basis of analyses of bond-pair types,mean square displacements,atomic density functions,and atom packing in different shells,it is shown that the structural changes in the Ti film could involve several stages owing to atomic position interchanging.In addition,the Ti or Al layers play an important role in the structural changes in Ti films.