Graphene Size Dependent Hardness and Strengthening Mechanisms of Cu/Graphene Composites:A Molecular Dynamics Study  

铜/石墨烯复合材料中石墨烯尺寸依赖的硬度及强化机制:分子动力学研究

作　　者：Zhang Shuang Chang Guo Li Liang Li Xiang Peng Haoran Chen Kaiyun Yang Nan Huo Wangtu 张霜;常国;李亮;李响;彭浩然;陈凯运;杨楠;霍望图(西北有色金属研究院先进材料研究所,陕西西安710016;西部金属材料股份有限公司联合技术中心,陕西西安710201)

机构地区：[1]Advanced Materials Research Center,Northwest Institute for Nonferrous Metal Research,Xi'an 710016,China [2]United Technology Center,Western Metal Materials Co.,Ltd,Xi'an 710201,China

出　　处：《稀有金属材料与工程》2025年第1期17-26,共10页Rare Metal Materials and Engineering

基　　金：Foundation of Northwest Institute for Nonferrous Metal Research(ZZXJ2203);Capital Projects of Financial Department of Shaanxi Province(YK22C-12);Innovation Capability Support Plan in Shaanxi Province(2023KJXX-083);Key Research and Development Projects of Shaanxi Province(2024GXYBXM-351,2024GX-YBXM-356);National Natural Science Foundation of China(62204207,12204383);Xi'an Postdoctoral Innovation Base Funding Program。

摘　　要：The extraordinary strength of metal/graphene composites is significantly determined by the characteristic size,distribution and morphology of graphene.However,the effect of the graphene size/distribution on the mechanical properties and related strengthening mechanisms has not been fully elucidated.Herein,under the same volume fraction and distribution conditions of graphene,molecular dynamics simulations were used to investigate the effect of graphene sheet size on the hardness and deformation behavior of Cu/graphene composites under complex stress field.Two models of pure single crystalline Cu and graphene fully covered Cu matrix composite were constructed for comparison.The results show that the strengthening effect changes with varying the graphene sheet size.Besides the graphene dislocation blocking effect and the load-bearing effect,the deformation mechanisms change from stacking fault tetrahedron,dislocation bypassing and dislocation cutting to dislocation nucleation in turn with decreasing the graphene sheet size.The hardness of Cu/graphene composite,with the graphene sheet not completely covering the metal matrix,can even be higher than that of the fully covered composite.The extra strengthening mechanisms of dislocation bypassing mechanism and the stacking fault tetrahedra pinning dislocation mechanism contribute to the increase in hardness.金属/石墨烯复合材料的卓越强度在很大程度上取决于石墨烯的特征尺寸、分布和形态。然而,石墨烯尺寸/分布对力学性能及相关强化机制的影响尚未完全阐明。在相同的石墨烯体积分数和分布条件下,通过分子动力学模拟研究了石墨烯片尺寸对复杂应力场下铜/石墨烯复合材料硬度和变形行为的影响,并建立单晶铜和石墨烯完全覆盖的铜基复合材料的2种模型作为对照。结果表明,强化效果随着石墨烯片尺寸的变化而变化。除了石墨烯位错阻挡效应和承载效应外,随着石墨烯片尺寸减小,变形机制依次从层错四面体、位错绕过、位错切过向位错形核变形机制转变。石墨烯片未完全覆盖铜基体的铜/石墨烯复合材料的硬度甚至高于完全覆盖的复合材料。经分析,位错挤出机制和汤普森四面体钉扎位错机制提供了额外的强化效应。

关 键 词：Cu/graphene composites graphene size HARDNESS strengthening mechanism molecular dynamics 

分 类 号：TB333[一般工业技术—材料科学与工程]