块体择优取向纳米孪晶铜的优异抗疲劳裂纹扩展性能  

Superior fatigue crack growth resistance in bulk Cu with highly oriented nanotwins

作　　者：赵瑞珂 赵怀智 卢磊 Ruike Zhao;Huaizhi Zhao;Lei Lu(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;Institute of Fluid Physics,China Academy of Engineering Physics,Mianyang 621999,China)

机构地区：[1]Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China [2]School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China [3]Institute of Fluid Physics,China Academy of Engineering Physics,Mianyang 621999,China

出　　处：《Science China Materials》2023年第11期4251-4257,共7页中国科学(材料科学(英文版)

基　　金：the financial support by the National Natural Science Foundation of China(NSFC,51931010,92163202);the Key Research Program of Frontier Science and International partnership program(GJHZ2029)。

摘　　要：本文研究了具有不同微观结构(如晶粒尺寸和孪晶厚度)的块体择优取向纳米孪晶Cu(NT-Cu)的疲劳裂纹扩展(FCG)特性,着重讨论了裂纹闭合效应和近门槛值区域的本征FCG阻力.与传统无孪晶的粗晶Cu相比,NT-Cu样品表现出显著提升的疲劳裂纹扩展抗力(有效门槛值应力强度因子范围,△K_(th,eff)).这种增强的裂纹扩展阻力与NT-Cu中特殊的跨孪晶位错滑移模式有关.该位错主导着NT-Cu裂纹尖端的循环变形,有效降低了裂纹尖端循环滑移不可逆水平,从而提高了纳米孪晶材料损伤扩展的本征抗力.We studied the fatigue crack growth(FCG)characteristics of bulk nanotwinned Cu(NT-Cu)with differ-ent microstructural aspects such as grain size and twin thickness.We specifically addressed the crack closure,with particular emphasis on the intrinsic FCG resistances in the near-threshold regime.The results demonstrate that the NT-Cu samples have significantly improved fatigue resistances compared with conventional twin-free polycrystalline Cu,a fact we measured using the effective threshold stress intensity factor range,∆_(Kth,eff).This enhanced resistance can be traced back to the activation of a specific set of primary slip systems in the NT-Cu,known as special trans-twin dislocation,which dominates the crack-tip cyclic deformation,leading to a di-minished level of cyclical slip irreversibility and,in turn,en-hancing the inherent resistance to damage propagation.

关 键 词：NANOTWINS fatigue crack growth rate crack closure effective crack growth threshold 

分 类 号：TG146.11[一般工业技术—材料科学与工程]