HCP-Mg平衡固液界面的微观结构

发布时间：2018-05-30 01:18

本文选题：HCP-Mg + 固液界面　；参考：《钢铁》2017年02期

【摘要】：采用NVE系综分子动力学(molecular dynamics,MD)方法模拟了HCP-Mg三个不同晶向的平衡固液界面,通过原子标定技术,在"layering and in-plane ordering"框架内,对固液界面的结构特征进行了分析。在验证了势函数有效性的基础上,通过界面微观结构分析发现,序参数在由固相向液相衰减的过程中呈现了很好的双曲正切的连续变化规律;以序参数aq6为标准计算得到的界面宽度要比序参数ξ的界面宽度大0.1~0.2 nm;同时,界面宽度存在各向异性,[0001]方向界面宽度最大,[11ˉ00]和[1ˉ21ˉ0]方向界面宽度基本相等,这与界面热力学的各向异性保持一致;界面的波动幅度达到界面宽度的5%~10%;此外,Layering方法定位的界面宽度要远远超过in-plane ordering方法定位的界面宽度,吻合于异质固液界面的试验观察。
[Abstract]:The equilibrium solid-liquid interface of three different crystal orientations of HCP-Mg was simulated by NVE molecular dynamics (MD) method. The structural characteristics of the solid-liquid interface were analyzed within the framework of "layering and in-plane ordering" by atomic calibration technique. On the basis of verifying the validity of the potential function, it is found that the order parameters show a good continuous variation law of hyperbolic tangent in the process of decay from solid phase to liquid phase through the microstructure analysis of the interface. The interface width calculated by using the ordered parameter aq6 as the standard is 0.1 ~ 0.2nm larger than that of the ordered parameter 尉, and the interface width is anisotropic, and the interface width in the [0001] direction is the largest, and the interface width in the direction of [11 ~ (00)] and [1] ~ (21) ~ (0) is basically equal. This is consistent with the anisotropy of interfacial thermodynamics, the fluctuation amplitude of the interface reaches 51010 of the interface width, and the interface width of the in-plane ordering method is much larger than that of the in-plane ordering method, which coincides with the experimental observation of the heterogeneous solid-liquid interface.
【作者单位】：省部共建高品质特殊钢冶金与制备国家重点实验室;上海市钢铁冶金新技术开发应用重点实验室;上海大学材料科学与工程学院;
【基金】：国家自然科学基金资助项目(51174131,51374141)
【分类号】：TG111.4

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