纳米多晶Cu-Ni合金拉伸行为的分子动力学模拟  

Molecular dynamics simulation on tensile behavior of nanocrystalline Cu-Ni alloys

作　　者：张国栋 赵俊生[1] 高帅 李秀春 李春建 ZHANG Guo-dong;ZHAO Jun-sheng;GAO Shuai;LI Xiu-chun;LI Chun-jian(College of Mechanical Engineering,North University of China,Taiyuan 030051,China)

机构地区：[1]中北大学机械工程学院,山西太原030051

出　　处：《塑性工程学报》2021年第9期194-199,共6页Journal of Plasticity Engineering

基　　金：山西省重点研发计划项目(201903D421035)。

摘　　要：为了研究平均晶粒尺寸和应变速率对Cu-Ni合金弹性模量和屈服强度的影响,采用分子动力学方法对纳米多晶CuNi合金在拉伸过程中的变形行为进行了模拟,建立了具有不同平均晶粒尺寸的5种Cu-Ni合金模型,对其弹性模量和屈服强度与平均晶粒尺寸的关系进行了系统地分析。结果表明,Cu-Ni合金的弹性模量和屈服强度随平均晶粒尺寸的增大而增大。对平均晶粒尺寸为10.66 nm的合金模型施加1×10^(9)~5×10^(9)s^(-1)的应变速率。结果表明,弹性模量受应变速率的影响较弱,屈服强度随应变速率的增加而增大。最后,根据位错的产生与演化,探讨了纳米多晶Cu-Ni合金在拉伸过程中的原子构型的变化情况,发现拉伸过程中位错更易在晶界处产生,位错滑移方向与拉伸方向成锐角或趋于一致。To study the effect of average grain size and strain rate on the elastic modulus and yield strength of Cu-Ni alloy,the deformation behavior of nanocrystalline Cu-Ni alloy during tensile process was simulated by molecular dynamics method.Five kinds of Cu-Ni alloy models with different average grain sizes were established,and the relationships between elastic modulus,yield strength and average grain size were systematically studied.The results show that the elastic modulus and yield strength of Cu-Ni alloy increase with the increases of average grain size.The strain rate of 1×10^(9)-5×10^(9) s^(-1) was applied to the alloy model with average grain size of 10.66 nm.The results show that the influence of strain rate on elastic modulus is weak,and the yield strength increases with the increase of strain rate.Finally,according to the generation and evolution of dislocations,the change of atomic configuration of nanocrystalline Cu-Ni alloy during tensile process was discussed.It is found that dislocations are more likely to occur at grain boundary during the tensile process,and the slip direction of dislocation is acute-angled or tends to be consistent with the tensile direction.

关 键 词：分子动力学 CU-NI合金 纳米多晶 晶粒尺寸 应变速率 

分 类 号：TG306[金属学及工艺—金属压力加工]