Intersectant coherent twin boundaries governed strong strain hardening behavior in nanocrystalline Cu

被引:27
作者
Cao, Z. H. [1 ]
Sun, W. [2 ]
Yang, X. B. [2 ]
Zhao, J. W. [2 ,3 ]
Ma, Y. J. [1 ]
Meng, X. K. [1 ]
机构
[1] Nanjing Univ, Coll Engn & Appl Sci, Natl Lab Solid State Microstruct, Inst Mat Engn, Nanjing, Jiangsu, Peoples R China
[2] Nanjing Univ, Sch Chem & Chem Engn, State Key Lab Analyt Chem Life Sci, Nanjing, Jiangsu, Peoples R China
[3] Jiaxing Univ, Sch Mat & Text Engn, Jiaxing, Zhejiang, Peoples R China
基金
中国国家自然科学基金;
关键词
Twin boundary; Sessile dislocation; Strain hardening; Plastic deformation; MOLECULAR-DYNAMICS SIMULATION; TAYLOR DISLOCATION MODEL; FCC METALS; MECHANICAL-PROPERTIES; NANOTWINNED METALS; DEFORMATION MECHANISMS; MAXIMUM STRENGTH; ANNEALING TWINS; COPPER; SIZE;
D O I
10.1016/j.ijplas.2018.01.002
中图分类号
TH [机械、仪表工业];
学科分类号
0802 ;
摘要
Introducing parallel coherent twin boundaries (p-CTBs) is a high effective approach to material strengthening. However, it has been widely verified that the strengthening effect of p-CTBs reaches saturation at a critical twin lamellar thickness. In this work, we demonstrate by experiments and molecular dynamic simulations that the novel intersectant coherent twin boundaries (i-CTBs) involving Lomer-Cottrell (L-C) dislocation locks trigger off a strong strain hardening on nanostructured metal, which exceeds the strength induced by p-CTBs strengthening. A transition from strain burst to dislocation multiplication occurs as the p-CTBs turn into i-CTBs in nanoscaled single crystals. The i-CTBs with different orientations can significantly promote the formation of L-C dislocation locks inside a nanocrystal, reflecting an intrinsic correlation between the i-CTBs and the L-C dislocation locks. The unique strain hardening primarily originates from the synergistic strengthening effect of the i-CTBs blocking and the L-C locks pinning on the glissile dislocation slip. These findings provide the impetus for a new strategy to design high strength and high plasticity crystalline materials.
引用
收藏
页码:81 / 94
页数:14
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