组元占比对层状纳米孪晶Cu力学行为的影响  

Effect of Component Proportion on Mechanical Behaviors of Laminated Nanotwinned Cu

作　　者：万涛 程钊[1] 卢磊[1] WAN Tao;CHENG Zhao;LU Lei(Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China)

机构地区：[1]中国科学院金属研究所沈阳材料科学国家研究中心,沈阳110016 [2]中国科学技术大学材料科学与工程学院,沈阳110016

出　　处：《金属学报》2023年第4期567-576,共10页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目Nos.51931010,92163202和52001312;中国科学院前沿科学重点研究计划项目No.GJHZ2029;中国科学院金属研究所创新基金项目No.2021-PY02;中国博士后科学基金Nos.BX20190336和2019M661150。

摘　　要：利用直流电解沉积制备了表层为硬组元、芯部为软组元的3种层状纳米孪晶(LNT)Cu样品,其中软组元占比分别为10%、50%和90%。研究发现:随软组元占比增加,拉伸屈服强度由425 MPa下降至262 MPa,均匀延伸率由5.7%增加至17%。3种LNT Cu的屈服强度均高于利用混合法则计算的平均强度,即表现出明显的额外强化。当组元占比为50%时,LNT Cu在变形过程中的应变局域化被很好地抑制,组元间应变差较小且相互约束作用强,额外强化效应最明显。Laminated metals have the potential for achieving better mechanical properties,such as higher strength,ductility,and work hardening ability.The mechanism that leads to these advances stems from the inhomogeneous plastic deformations between soft and hard components where geometrically necessary dislocations(GNDs)are produced while the two adjacent components are mutually constrained.Many structural factors have already been extensively investigated during the optimization of the laminated structure,such as the effect of layer thickness and the strength differential between components on the overall resulting properties.However,the effect of component composition percentage,an important factor for laminated structures,on the mechanical properties and its underlying mechanism remains elusive.To unravel the effect of component composition percentage on the mechanical properties,we used stable nanotwinned structures as components to build laminated nanotwinned(LNT)Cu materials.Three LNT Cu samples with hard components on the surface layers and soft components in the core layer were designed and prepared by direct-current electrodeposition.The soft component percentages were set as 10%,50%,and 90%.The mechanical behaviors of LNT Cu were explored by uniaxial tensile tests at room temperature.Yield strengths for all three LNT Cu were higher than that estimated by the rule of mixture,indicating an extra strengthening effect from the LNT structure.The LNT Cu containing 50%soft component(LNT-50%)demonstrated the greatest extra strengthening.Interestingly,full-field strain measurements and microstructure characterizations further indicated that the strain localization of LNT-50%was well suppressed and the lateral strain difference between the soft and hard components was obviously reduced.This indicated that the strong mutual constraint between the two components contributed to the greatest extra strengthening.

关 键 词：层状纳米孪晶Cu 组元占比 额外强化 应变局域化 梯度塑性变形 

分 类 号：TG146[一般工业技术—材料科学与工程]