微观尺度下单晶铜熔点多因素影响的分子动力学模拟研究

基于分子动力学方法,利用嵌入原子势(EAM)函数,在微观尺度下研究了影响单晶铜熔点的多种因素。首先利用势函数计算单晶铜的晶格常数和弹性常数,以此验证本研究所采用势函数的准确性,然后利用能量体积法、径向分布函数法和键对分析技术对模拟得到的结果进行分析,测得单晶铜熔点约为1 380K。分析了模型大小、升温速率、晶体缺陷对铜熔点的影响,研究发现模型大小、升温速率对熔点的影响不大,随着升温速率的增大,达到熔点所需的时间越短。晶体缺陷的存在使金属材料晶格点阵稳定性下降,熔化需要的热量减少,熔点相应降低,与实际熔点情况一致。

Microscale Molecular Dynamics Simulation of Different Factors Influence on Melting Point of Single Crystal Copper

Based on the molecular dynamics method,the melting process of single crystal copper was simulated by embedded atom potential (EAM) functior.Firstly,using the potential function,the lattice constants and elastic constants of single crystal copper were calculated to verify the accuracy of the selected potential function,which ensured the accuracy of the calculation of the melting point of single crystal copper.Then,energy volume method,radial distribution function method and bond pair analysis technique were adopted to analyze the simulation results.The conclusion was that the melting point of single crystal copper was about 1380 K.At the same time,the influence of model size,heating rate,crystal defects on melting point were also analyzed.It could be found that the model size and heating rate had little effect on the melting point.As the heating rate increased,the time required to reach the melting point was shorter.The existence of crystal defects leaded to the decrease of lattice stability of metallic materials,a reduction in the quantity of heat required by melting and a corresponding decrease of the melting point.Through the calculation and analysis,the melting point of single crystal copper in this paper was in line with the actual melting point.