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.
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)
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)。
