化学序对NiCoCr中熵合金力学性能影响的分子动力学模拟  

Molecular dynamics simulation of the effect of chemicalshort-range order on mechanical properties of NiCoCr medium-entropy alloy

作　　者：郝士凯 梁凯 康恒 潘少鹏 牛晓峰[1] 乔珺威[1] 宋凯凯 王伟民[5] 秦敬玉[5] HAO Shikai;LIANG Kai;KANG Heng;PAN Shaopeng;NIU Xiaofeng;QIAO Junwei;SONG Kaikai;WANG Weimin;QIN Jingyu(College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Department of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China;Beijing Computational Science Research Center,Beijing 100193,China;School of Mechanical,Electrical&Information Engineering,Shandong University,Weihai 264209,China;Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education),Shandong University,Jinan 250061,China)

机构地区：[1]太原理工大学材料科学与工程学院,太原030024 [2]北京科技大学材料科学与工程学院,北京100083 [3]北京计算科学研究中心,北京100193 [4]山东大学机电与信息工程学院,山东威海264209 [5]山东大学材料液固结构演变与加工教育部重点实验室,济南250061

出　　处：《功能材料》2023年第6期6194-6200,6223,共8页Journal of Functional Materials

基　　金：国家自然科学基金项目(51701135,51871132,51874209,52071229)。

摘　　要：采用蒙特卡洛和分子动力学模拟(MD)方法研究化学序(CSRO)对NiCoCr中熵合金(MEA)力学性能的影响规律。基于信息熵提出了一个描述化学序的参数S,其值越小体系的化学序越强。模拟结果表明体系平均原子体积和势能随着S减小而减小,且体系结构更加稳定。接着,对NiCoCr中熵合金进行压缩模拟,模型的屈服强度随着S的减小呈现增加趋势。进一步数据分析发现,Cr原子以及具有多配位Cr原子的中心原子更容易变形,而具有多配位Ni或Co原子的中心原子则倾向于更难变形。由此可知,通过改变化学序和Cr原子的含量能提升NiCoCr高熵合金的力学性能,此结果为实验制备具有更优异性能的高熵合金提供了有价值的参考。The effect of chemical short-range order on the mechanical property of NiCoCr medium-entropy alloys(MEA)was investigated via Monte Carlo methods and molecular dynamics simulations.Based on the information entropy of the composition of the crystalline cell,a new parameter expressed by S,was proposed to describe the degree of chemical short-range order in the MEA with the smaller the value the stronger the chemical order of the system.It is found that the average atomic volume and the potential energy decrease with the decrease of S of the MEA,which indicates that stronger chemical short-range order can encourage the structures to be stable.Then,compress simulations were carried out for the NiCoCr MEA,and the yield strength of the model showed an increasing trend with decreasing S.Further studies found that Cr atoms in the MEA are more prone to deform during the compression.It is also demonstrated by the evidence that the atoms with more coordinated Cr atoms are more easily deformed while the atoms with more coordinated Ni or Co atoms tend to deform with more difficulty.It can be found that the mechanical properties of NiCoCr MEAs can be improved by changing the CSRO and reducing the Cr concentration.These findings provide a valuable reference for the experimental preparation of high entropy alloys with better properties.

关 键 词：化学序 中熵合金 分子动力学模拟 力学性能 

分 类 号：TG139[一般工业技术—材料科学与工程]