镍基Al_(x)CoCrFeNi高熵合金涂层升温摩擦性能的原子尺度分析  

Molecular Dynamics Simulation of Al_(x)CoCrFeNi High Entropy Alloy Coating at High Temperature

作　　者：吴灿 孙虎儿[1,2] 杨超毅 WU Can;SUN Huer;YANG Chaoyi(Mechanical Engineering College,North University of China,Shanxi Taiyuan 030051,China;Upgrading office of Modern College of Humanities and Sciences of Shanxi Normal University,Shanxi Linfen 041000,China)

机构地区：[1]中北大学机械工程学院,山西太原030051 [2]山西师范大学现代文理学院转设筹备处,山西临汾041000

出　　处：《摩擦学学报（中英文）》2024年第4期530-541,共12页Tribology

基　　金：山西省基础研究计划项目(202103021223196)资助。

摘　　要：高熵合金(HEAs)具有较高的硬度、耐磨性和抗氧化性,是1种有前景的高温涂层材料.采用分子动力学仿真,分析了在300~1500 K温度条件下,Ni基板上Al_(x)CoCrFeNi(x=0,3,6,10)高熵合金涂层在划伤过程中的力学特性和摩擦磨损行为.结果表明:Al_(x)CoCrFeNi HEA涂层法向和切向摩擦力随着Al含量增加和温度的升高而逐渐减小,摩擦系数波动幅度较小,随着Al含量增加而先减小后增大,在1500 K时,Al_(10)CoCrFeNi涂层的摩擦系数最大,为0.529.损伤原子位移及剪切应变与Al含量和温度呈正相关,Al含量的增加或温度的升高降低了摩擦表面的剪切强度,使损伤原子数目增加,材料形变均匀性降低.相结构、位错缺陷等特性与Al含量及温度密切相关,随着Al含量增加和温度上升,FCC相原子含量减少,材料塑性降低,涂层中BCC相和其他相结构原子的比例增多.在高温下缺陷产生的深度更深,但位错密度降低,这表明在高温下位错的迁移难度降低,位错对材料的强化程度降低,材料亚表层的破坏程度逐渐严重.Al_(x)CoCrFeNi涂层与Ni基板界面的结合强度随着Al含量的增加而降低,随着温度的上升而逐渐增大,HEA涂层与Ni基底界面处的应力是影响界面结合强度的因素之一,x=0时涂层界面应力明显高于其他3种情况.High-entropy alloys(HEAs)possess excellent mechanical and tribological properties,making them a promising material for high-temperature coatings.Al_(x)CoCrFeNi(x=0,3,6,10)high entropy alloy coatings were formulated on Ni substrates to augment their wear and oxidation resistance,thus broadening the application scope of Ni and its alloys.In this study,the mechanical properties and friction and wear behavior of Al_(x)CoCrFeNi(x=0,3,6,10)high entropy alloy coatings on Ni substrates were analyzed at temperatures ranging from 300~1500 K by molecular dynamics simulations,where the molecular dynamics model incorporated both the Ni-based coatings and spherical diamond abrasives.Throughout the scratching process,the abrasive particle moved along the positive x-direction at a predetermined speed of 100 m/s.The results demonstrated that the normal and tangential friction forces of Al_(x)CoCrFeNi HEA coatings progressively decreased with increasing Al content,exhibiting a negative correlation with temperature.Furthermore,with the increase of Al content,the average normal and tangential friction forces also decreased accordingly,and the maximum reduction was 46.74%when x=10.During the scratching process of Al_(x)CoCrFeNi HEA coatings,the overall fluctuation of the average friction coefficient was small,initially decreasing and then increasing with the increase of Al content.At 1500 K,Al_(10)CoCrFeNi coating showed the maximum friction coefficient,at 0.529.The displacement of damaged atoms and the shear strain of the coating were positively correlated with Al content and temperature.The increase of Al content or temperature reduced the shear strength of the friction surface,resulting in an increasing number of damaged atoms and a deterioration in the uniformity of material deformation.The primary damaged atoms were identified as abrasive dust atoms,which accumulated unevenly on either side of the scratch,exhibited various shapes,and increased proportionally with the distance of the scratch.As the temperature rose,the shear stra

关 键 词：高熵合金 涂层 摩擦磨损 界面结合强度 分子动力学 

分 类 号：TH117.1[机械工程—机械设计及理论]