Effect of volume fractions of gradient transition layer on mechanical behaviors of nanotwinned Cu

被引:51
作者
Cheng, Zhao [1 ]
Wan, Tao [1 ,2 ]
Bu, Linfeng [1 ,3 ]
Lu, Lei [1 ]
机构
[1] Chinese Acad Sci, Shenyang Natl Lab Mat Sci, Inst Met Res, Shenyang 110016, Peoples R China
[2] Univ Sci & Technol China, Sch Mat Sci & Engn, Shenyang 110016, Peoples R China
[3] Univ Sci & Technol China, CAS Ctr Excellence Complex Syst Mech, Dept Modern Mech, CAS Key Lab Mech Behav & Design Mat, Hefei 230027, Peoples R China
基金
中国博士后科学基金; 中国国家自然科学基金;
关键词
Heterogeneous nanostructured metals; Gradient transition layer; Strengthening behavior; Distribution of GNDs; Back stress; LATTICE PLANE MISORIENTATIONS; BACK STRESS; STAINLESS-STEEL; FLOW-STRESS; PLASTICITY; DEFORMATION; DISLOCATIONS; STRENGTH; ORIENTATION; DEPENDENCE;
D O I
10.1016/j.actamat.2022.118456
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Heterogeneous nanostructured (HNS) materials, such as gradient and laminated nanostructured metals, possess superior mechanical properties with respect to their homogeneous counterparts. The additional strengthening mechanism of HNS is mainly attributed to the non-uniform plastic deformation induced by gradient transition layers (GTLs) between components. Here, we designed three gradient nanotwinned (GNT) Cu samples with different volume fractions of GTLs ( f g ) of 10%, 50% and 100% while the rule-ofmixture strength and overall structural gradient are constant to quantitatively reveal its effect on the extra strengthening behaviors. As f g increases, the yield strength is improved and the elastic to plastic stage is prolonged at small strain. Moreover, larger f g suppresses the strain localization and reduces nucleation of cracks at larger strain, accompanied by more widely distributed geometrically necessary dislocations (GNDs) and more bundles of concentrated dislocations (BCDs), thus improving the elongation. Stress partitioning analysis and numerical simulations show that the more widely-distributed GNDs at larger f g result in higher overall back stresses but hardly affect effective stresses, indicative of the origin of the improved strengthening. Such GND-distribution dominated strengthening mechanism paves a fundamental way for developing higher-performance HNS materials.(c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
引用
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页数:12
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