论文部分内容阅读
根据改进分析型嵌入原子法(MAEAM),利用分子动力学(MD)模拟研究含表面薄W(111)和W(110)晶面熔化机制。首先研究温度对晶面表层原子均方位移(MSD)的影响,表明表面和非谐效应对晶面结构和性质影响明显,且原子振动呈现各向异性的特点。在此基础上进一步分析其原子密度函数(ADF)和结构因子(SF)随温度变化,发现薄W(111)和W(110)晶面熔化机制不同,对于W(111)晶面,表面在其熔化转变过程中起主要作用,在3700K完全熔化,拟合无序原子分数随温度变化表明W(111)晶面预熔-熔化转变温度为3550K;而W(110)晶面则出现过热,直到4000K完全熔化,非谐效应在其熔化转变中起主要作用。
Based on the improved analytic embedded atom method (MAEAM), the melting mechanism of the thin W (111) and W (110) planes with surface was investigated by molecular dynamics (MD) simulation. Firstly, the effect of temperature on the mean square displacement (MSD) of the crystal surface was investigated. It is shown that the surface and the anharmonic effect have obvious effects on the structure and properties of the crystal plane, and the vibration of the atom is anisotropic. On the basis of this, we further analyze the change of atomic density function (ADF) and structure factor (SF) with temperature, and find that the melting mechanism of thin W (111) and W (110) planes is different. The melting temperature of W (111) crystal surface was 3550K, while that of W (110) crystal surface was overheating, Until 4000K is completely melted, the aharmonic effect plays a major role in its melting transition.