具有高度(220)取向垂直纳米孪晶异质结构铜薄膜的强化机制研究  

Strengthening mechanisms in heterostructured copper films with highly(220)-oriented vertical nanotwins

作　　者：韦小丁 张鹏 马瑜薇 刘俊杰 於中良 丛超男 Xiaoding Wei;Peng Zhang;Yuwei Ma;Junjie Liu;Zhongliang Yu;Chaonan Cong(State Key Laboratory for Turbulence and Complex System,Department of Mechanics and Engineering Science,College of Engineering,Peking University,Beijing,100871,China;Institute for Advanced Materials and Technology,University of Science and Technology Beijing,Beijing,100083,China;Department of Engineering Mechanics,Beijing University of Technology,Beijing,100124,China;College of Mechanical Engineering,Yangzhou University,Yangzhou,225127,China;College of Science,China Agricultural University,Beijing,100083,China)

机构地区：[1]State Key Laboratory for Turbulence and Complex System,Department of Mechanics and Engineering Science,College of Engineering,Peking University,Beijing,100871,China [2]Institute for Advanced Materials and Technology,University of Science and Technology Beijing,Beijing,100083,China [3]Department of Engineering Mechanics,Beijing University of Technology,Beijing,100124,China [4]College of Mechanical Engineering,Yangzhou University,Yangzhou,225127,China [5]College of Science,China Agricultural University,Beijing,100083,China

出　　处：《Acta Mechanica Sinica》2024年第1期44-53,共10页力学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.12172005,11988102,and 11890681);the National Key R&D Program of China(Grant Nos.2022YFB3806100 and 2020YFE0204200).

摘　　要：在本工作中,我们通过直流电沉积方法制备了含有不同体积比的(220)取向垂直纳米孪晶异质结构的铜薄膜,并表征了其力学性能.单轴拉伸测试表明,当垂直纳米孪晶的体积比增加时,机械性能显著提高:具有88%垂直孪晶的薄膜的极限拉伸强度为455 MPa,约比等轴晶粒铜薄膜的强度高83%.通过对拉伸后样品进行高分辨电子显微镜表征,并辅以分子动力学模拟,我们揭示了含有等轴晶粒和垂直纳米孪晶的特殊异质结构有助于激活铜薄膜材料内部多种模式的滑移系统,并导致更高的位错密度,从而在赋予材料更强的机械强度和加工硬化率的同时,不会显著损失材料的韧性.In this study,heterostructured copper films containing different proportions of highly(220)-oriented vertical nanotwins were prepared by direct current(DC)electroplating.Uniaxial tensile tests showed that the mechanical properties improved notably when the volume ratio of the vertical nanotwins increased—the film with the 88%vertical twins exhibited the ultimate tensile strength of 455 MPa,approximately 83%higher than those of the equiaxed Cu films.Postmortem electron microscopy characterizations,assisted by molecular dynamics simulations,revealed that these special heterostructures of the equiaxed grains and vertical nanotwins facilitated the activation of multi-mode slip systems.The activation of multi-mode slip systems leads to higher dislocation density,thus endowing the material with enhanced mechanical strength and work hardening rate without significant loss of ductility.

关 键 词：纳米孪晶 高分辨电子显微镜 极限拉伸强度 异质结构 铜薄膜 等轴晶粒 滑移系统 强化机制 

分 类 号：TB383[一般工业技术—材料科学与工程]