通过分子动力学 (molecular dynamics, MD) 模拟, 研究了 Cu₅₀Ni₅₀ 合金在不同温度下凝固及其退火过程的空位捕获. 结果发现: 凝固过程中的空位捕获效应, 即被捕获空位浓度的过饱和现象非常明显; 随着凝固温度的降低, 空位浓度显著上升, 与平衡浓度随温度的变化规律正好相反; Cu₅₀Ni₅₀ 存在一个特征温度 T ^∗, 在 T > T ^∗ 浅过冷温度下, 凝固速度随着凝固温度的降低快速增加, 在 T < T ^∗ 深过冷温度下, 凝固速度随着凝固温度的降低缓慢下降,表明空位浓度并不是界面生长速度的单值函数; 作为合金元素, Cu 比 Ni 更倾向于形成空位原子 (vacancy atom, VA).

Molecular dynamics (MD) simulation was used to investigate the vacancy trap-ping during the solidification and annealing processes of Cu₅₀Ni₅₀ at different temperatures. The results showed that the vacancy trapping effect was very evident and the vacancy concentration significantly increased with the decrease in temperature, opposite to the law that the equilibrium concentration changes with temperature. There was a characteristic temperature T ^∗ for which the solidification rate rapidly increased with the decrease of temperature at shallow undercooling when T > T ^∗ but decreased slowly at deep undercooling when T < T ^∗, indicating that the vacancy concentration was not a monotonic function of the interface moving rate. In addition, as an alloy constituent, Cu was found to be a better vacancy atom (VA) than Ni.