Au快速凝固及晶体生长的分子动力学模拟

Molecular dynamics simulation of high-speed solidification and crystal growth of gold(Au)

为了研究液态金属在液固相变过程中的微观结构及热力学性质,采用Embedded-Atom Method(EAM)作用势函数,利用分子动力学方法模拟了液态Au凝固过程中不同冷却速度和压力下的热力学及动力学性质,并用固液两层构型的方法模拟了Au的晶体生长过程.模拟结果表明在相同压力下,冷却速度快时,形成非晶体;冷却速度慢时,形成晶体.在同一冷却速度下,压力越大,结晶温度越高.采用较慢的冷却速度并增加压力,可以使结晶过程进行得更充分,得到的结构更稳定.

To study the microstructure and thermodynamics during the solidification process of liquid metals, the molecular dynamics simulation by using the embedded-atom method （EAM） was conducted to investigate the effects of the cooling rate and external pressure on the solidification process of liquid gold Au. The crystal growth process of liquid Au was simulated by using a two-layer solid-liquid configuration model. The simulation results show that the liquid Au is solidified into the amorphous solid at a high cooling rate and into crystal at a relatively lower cooling rate under the definite external pressure. Under a definite cooling rate, higher the pressure is, higher the crystallization temperature is. Using the lower cooling rate and higher external pressure, the crystallization process is shown to be more sufficient and the molecular structure is more stable.