高熵合金CoCrFeMnNi尺寸依赖性的纳米压痕模拟  

Nanoindentation Simulation of the Size Dependence of the High-Entropy Alloy CoCrFeMnNi

作　　者：牛帅 张灿[1] 师明星 NIU Shuai;ZHANG Can;SHI Mingxing(School of Mechanics and Aerospace Engineering,Southwest Jiaotong University,Chengdu 611756,China)

机构地区：[1]西南交通大学力学与航空航天学院,成都611756

出　　处：《四川轻化工大学学报（自然科学版）》2024年第2期1-8,共8页Journal of Sichuan University of Science & Engineering(Natural Science Edition)

基　　金：国家自然科学基金项目(11472229)。

摘　　要：采用分子动力学方法模拟了CoCrFeMnNi高熵合金的纳米压痕变形过程,并针对压头尺寸和压入晶向两种因素对该材料力学性能影响方式及其相应的微观结构演化机理进行了研究。通过赫兹曲线拟合验证了模拟的正确性,研究结果表明:随着压头半径从3 nm增至6 nm,材料会出现塑性延迟现象,且硬度随之减小,沿[001]、[110]、[111]3种压入方向分别减少了9.78%、4.62%和12.97%;随压头尺寸的增大,位错长度和密度整体均呈增长趋势;但当压头尺寸增大到一定程度时,沿着晶向[110]、[111]的压入过程中会出现位错环脱落现象,导致在个别工况下位错密度并无增长。整体上看,随着压头尺寸的增大,CoCrFeMnNi高熵合金材料中开动的滑移系增多,并且塑性变形增大。A molecular dynamics method is used to simulate the nanoindentation deformation process of CoCrFeMnNi high-entropy alloy.Aiming at the two factors of indenter size and indentation crystal orientation,the way of influencing the mechanical properties of this material and the corresponding microstructure evolution mechanism are investigated.The correctness of the simulation is verified by Hertzian curve fitting,and the results of the study show that as the size of the indenter increases from 3 nm to 6 nm,the material undergoes a plastic delay phenomenon and the hardness decreases with the change,decreasing by 9.78%,4.62%,and 12.97%along the three indentation directions[001],[110]and[111],respectively;both the dislocation length and the dislocation density show an overall increasing trend with increasing indenter size;but when the size of the indenter increases to a certain extent,the dislocation loop detachment phenomenon occurs during the indentation process along the grain direction[110],[111],resulting in no growth of dislocation density under individual working conditions.Overall,as the size of the indenter increases,there is an increase in the number of open slip systems in the CoCrFeMnNi high-entropy alloy material and an increase in plastic deformation.

关 键 词：分子动力学 纳米压痕模拟 压头尺寸 硬度 位错 

分 类 号：O34[理学—固体力学]