纳米晶Cu-Ag双峰合金材料热导率的分子动力学模拟研究

摘要

In the paper,the preparison method of nanocrystalline alloy was described and bimodal nanocrystalline Cu-Ag was obtainedby high pressure sintering method in argon atmosphere.The equilibrium molecular dynamics is also used to study the effects ofgrain size and temperature on the thermal conductivity ofnc Cu-Ag at 100-300 K.The effect of theaverage grain size on the thermal conductivity of nc Cu-Ag is investigated by optimizing the cut-off radius and the time step for initial condition of molecular dynamics.At the same time,the results of simulation and experiment results were compared,which show that the simulation results are basically identical with the experimental data.The thermal conductivity of nc Cu-Ag is lower than the coarse grained copper or silver.The decrease of the thermal conductivity of nc Cu-Ag can be mainly attributed to the nano-size effect,due to the reduction of heat transport carrier concentration in fine crystalline structure and strong scattering of carriers at the interface of Cu/Ag nanoparticles.%描述了一种制备纳米晶合金的方法,获得纳米晶Cu-Ag双峰材料.采用分子动力学方法研究了温度在100～-300 K范围内纳晶Cu-Ag双峰材料的热导率随尺寸和温度的变化关系.在对初始截断半径和时间步长进行设置和优化的条件下,计算并分析了平均晶粒尺寸热导率的影响规律.同时,对模拟结果和实验测试结果进行对照,结果表明:模拟结果与实验数据基本一致,纳晶Cu-Ag双峰材料热导率明显低于单晶Cu/Ag块体,存在明显的尺寸效应.其原因主要与细晶组织中热输运载流子浓度的降低以及载流子在Cu/Ag纳晶晶粒界面上的强烈散射有关.