Mg-Al合金熔体中固液界面结构的分子动力学研究

Molecular dynamics study of solid-liquid interface structure in Mg-Al alloy melt

本文采用分子动力学研究了Mg-3%Al合金熔体中固液界面结构及界面附近原子的扩散行为.计算结果表明,该二元合金的固液界面为粗糙界面.垂直于界面方向的数密度分布,表现出复杂波动的特征,这种波动一直延伸到液体中.在界面附近的区域,扩散系数的三个不同方向的分量表现出了明显的各向异性,并且这种各向异性一直持续到液相当中.对界面二维结构的分析表明,界面附近液相原子的二维排列呈现出从长程有序逐渐过渡到短程有序的变化.

The solid-liquid(S-L)interfacial structure and the atomic diffusion behavior of Mg-3% Al alloy melt were investigated by using molecular dynamics simulations method(MD).The results show that the S-L interface of the Mg-Al binary alloy is a rough interface.The number density distribution along the normal direction of S-L interface exhibits complex fluctuations,which extends into the liquid phase.In the vicinity of the interface,the diffusion coefficients of three directions exhibit distinct anisotropy,which extends into the liquid phase too.Analysis on the two-dimensional interfacial structure shows the transition from long-range order to short-range order for arrangement of liquid atoms near the S-L interface.