W/Ta纳米层状金属的拉伸力学性能和塑性变形机制  

Mechanical properties and plastic deformation mechanisms of W/Ta nanoscale metallic multilayer under tension

作　　者：刘雪鹏 颜家豪 LIU Xuepeng;YAN Jiahao(Department of Engineering Mechanics,College of Civil Engineering,Hefei University of Technology,Hefei 230009,China;Department of Mechanical Design Engineering,School of Mechanical Engineering,Hefei University of Technology,Hefei 230009,China;Anhui Province Key Lab of Aerospace Structural Parts Forming Technology and Equipment,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]合肥工业大学土木与水利工程学院工程力学系,安徽合肥230009 [2]合肥工业大学机械工程学院机械设计工程系,安徽合肥230009 [3]合肥工业大学航空结构件成形制造与装备安徽省重点实验室,安徽合肥230009

出　　处：《振动工程学报》2025年第3期637-644,共8页Journal of Vibration Engineering

基　　金：国家自然科学基金资助项目(12272118);国家磁约束核聚变能发展研究专项项目(2022YFE03030003)。

摘　　要：W/Ta纳米层状金属是一种典型的BCC/BCC结构的层状金属材料,在核聚变装置中具有广阔的应用前景。本文采用原子尺度分子动力学方法研究了W/Ta纳米层状金属在单轴拉伸过程中的力学性能和塑性变形行为,进一步分析了调制周期对W/Ta纳米层状金属力学响应的影响。结果表明,W(110)/Ta(110)界面上会形成网络状的失配位错结构,它不仅可以作为位错形核的源头,而且可以吸收层状金属结构中的位错。微结构演化分析表明,拉伸过程中主要经历三个变形阶段,即线弹性、塑性屈服和塑性流变阶段。位错首先在Ta层中形核扩展,导致应力急剧下降,随后Ta层中的位错穿越界面至W层中并增殖扩展,导致W层发生屈服。试样的塑性屈服主要由Ta层主导,流变阶段的塑性变形由W层和Ta层中的位错及其演化共同决定。调制周期越大,界面数量越少,Ta层中位错形核较少,同样位错被界面吸收的数量较少而且界面阻碍位错的效果减弱,因此屈服强度和平均塑性流变强度分别增加和降低。W/Ta nanoscale metallic multilayer is a typical body-centered cubic/body-centered cubic nanolayered composite,which is very promising for the application in nuclear fusion devices.Based on atomistic molecular dynamic(MD)simulations,we investigate the mechanical properties and plastic deformation mechanisms of W/Ta nanolayered composite under uniaxial tension,and further analyze the influence of modulation period on the mechanical response of W/Ta nanolayered composite.The results show that the W(110)/Ta(110)interface forms a misfit dislocation network,which can not only serve as the source for dislocation nucleation but also adsorb the dislocations in the metallic multilayer.The microstructure evolution analysis shows that,W/Ta nanolayered composite mainly experiences three deformation stages during stretching,i.e.linear elastic,plastic yield,and plastic flow stages.The dislocations firstly nucleate and propagate in the Ta layers,which leads to the sharp drop in the stress-strain curve.Subsequently,the dislocations in the Ta layers pass through the interfaces and enter into the W layers,and the propagation and slip of the dislocations in the W layers cause the yield of W layers.The yield of the sample is primarily determined by the Ta layers,and the plastic deformation in the flow stage is jointly governed by the dislocations and their evolution in both the W and Ta layers.With an increase of modulation period,the number of interfaces in the W/Ta metallic multilayer decreases,so that the nucleation of dislocations decreases as well as the amount of dislocations adsorbed by the interfaces decreases.In addition,the decreased number of the interface weakens the effect of hindering dislocations by interface.Therefore,the yield strength increases and the averaged plastic flow strength decreases.

关 键 词：纳米层状金属 分子动力学模拟 力学性能 塑性变形机制 调制周期 

分 类 号：TB383[一般工业技术—材料科学与工程] O313.1[理学—一般力学与力学基础]