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运用分子动力学模拟方法,采用镶嵌原子势,研究了金属Au和AuAu′(Au为正常尺寸的金原子,Au′为半径尺寸变大10%的金原子,两者的原子比例为3:1)在发生玻璃转变过程中的势能曲面,探讨了原子尺寸差效应对势能曲面的影响.我们发现增加原子尺寸差会导致Au的势能曲面发生显著的变化:它使高-低温的内在势能差变大;导致每个温度下内在能量分布变宽,势能曲面变得粗糙;使得体系的海森矩阵特征值分布曲线的峰值变矮,势能曲面上的结构重排方向更少,重排几率更小;导致过冷液态区的流变激活能随温度降低增加更快.以上原子尺寸差效应导致的势能曲面的所有的变化,都有利于提高非晶的形成能力.
Using the method of molecular dynamics simulation, using the inlaying atomic potential, the metal Au and AuAu ’(Au is a gold atom with a normal size, Au’ is a gold atom with a radius of 10% larger, the atomic ratio between the two is 3: 1 ) On the surface of potential energy in the process of glass transition, we discuss the effect of atomic size difference effect on the potential energy surface.We find that increasing the atomic size difference leads to a significant change in the potential energy surface of Au: it changes the intrinsic potential difference between high and low temperature Which leads to the broadening of the internal energy distribution and the rough surface of the potential energy at each temperature. As a result, the peak value of the Eisenia matrix eigenvalue distribution curve of the system becomes shorter, the direction of structure rearrangement on the potential energy surface is smaller and the rearrangement probability is smaller ; The rheological activation energy of the supercooled liquid region increases rapidly with decreasing temperature. All the changes in the potential energy surface caused by the above atomic size difference effect are conducive to improving the formation ability of the amorphous.