| On strain hardening mechanism in gradient nanostructures |
| Li JJ; Weng GJ; Chen SH(陈少华) ; Wu XL(武晓雷); Li, JJ (reprint author), Northwestern Polytech Univ, Sch Mech Civil Engn & Architecture, Dept Engn Mech, Xian 710129, Shaanxi, Peoples R China.
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| 发表期刊 | INTERNATIONAL JOURNAL OF PLASTICITY
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| 2017
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| 卷号 | 88页码:89-107 |
| ISSN | 0749-6419
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| 摘要 | Experiments have shown that a gradient design, in which grain size spans over four orders of magnitude, can make strong nanomaterials ductile. The enhanced ductility is attributed to the considerable strain hardening capability obtained in the gradient metals. A non-uniform deformation on the lateral sample surface is also observed. This might inject geometrically necessary dislocations (GNDs) into the sample. However, no direct evidence has been provided. Therefore the issues remain: why can the gradient structure generate high strain hardening, and how does it reconcile the strength-ductility synergy of gradient nanostructures? Here for the first time we quantitatively investigate the strain hardening of a gradient interstitial-free steel by developing a dislocation density-based continuum plasticity model, in which the interaction of the component layers in the gradient structure is represented by incorporating GNDs and back stress. It is demonstrated that both the surface non-uniform deformation and the strain-hardening rate up-turn can be quantitatively well predicted. The results also show that the strain hardening rate of the gradient sample can reach as high as that of the coarse-grained counterpart. A strength-ductility map is then plotted, which clearly show that the gradient samples perform much more superior to their homogeneous counterparts in strength-ductility synergy. The predicted map has been verified by a series of experimental data. A detailed analysis on GNDs distribution and back stress evolution at the end further substantiates our view that the good strain hardening capability results from the generation of abundant GNDs by the surface non-uniform deformation into the nano-grained layers of the gradient sample. (C) 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
| 关键词 | Ductility
Dislocations
Constitutive Behavior
Inhomogeneous Material
Analytic Functions
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| DOI | 10.1016/j.ijplas.2016.10.003
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| URL | 查看原文
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| 收录类别 | SCI
; EI
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| 语种 | 英语
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| WOS记录号 | WOS:000389105300005
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| 关键词[WOS] | Ductility
; Dislocations
; Constitutive behavior
; Inhomogeneous material
; Analytic functions
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| WOS研究方向 | Engineering
; Materials Science
; Mechanics
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| WOS类目 | Engineering, Mechanical
; Materials Science, Multidisciplinary
; Mechanics
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| 项目资助者 | Alexander von Humboldt Foundation
; National Natural Science Foundation of China [11402203]
; Fundamental Research Funds for the Central Universities [3102015BJ(II)JGZ025]
; NSF Mechanics of Materials and Structures Program [CMMI-1162431]
; NSFC [11372317, 11532013, 11572328]
; 973 Nano-project [2012CB937500]
; 973 Program [2012CB932203]
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| 课题组名称 | LNM材料介观力学性能的表征
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| 论文分区 | 一类
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| 力学所作者排名 | 4
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| 引用统计 |
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| 文献类型 | 期刊论文
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| 条目标识符 | http://dspace.imech.ac.cn/handle/311007/59943
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| 专题 | 非线性力学国家重点实验室
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| 通讯作者 | Li, JJ (reprint author), Northwestern Polytech Univ, Sch Mech Civil Engn & Architecture, Dept Engn Mech, Xian 710129, Shaanxi, Peoples R China. |
推荐引用方式
GB/T 7714 |
Li JJ,Weng GJ,Chen SH,et al. On strain hardening mechanism in gradient nanostructures[J]. INTERNATIONAL JOURNAL OF PLASTICITY,2017,88:89-107.
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| APA |
Li JJ,Weng GJ,陈少华,武晓雷,&Li, JJ .(2017).On strain hardening mechanism in gradient nanostructures.INTERNATIONAL JOURNAL OF PLASTICITY,88,89-107.
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| MLA |
Li JJ,et al."On strain hardening mechanism in gradient nanostructures".INTERNATIONAL JOURNAL OF PLASTICITY 88(2017):89-107.
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