IMECH-IR  > 非线性力学国家重点实验室
Dislocation nucleation governed softening and maximum strength in nano-twinned metals
Li XY; Wei YJ(魏宇杰); Lu L; Lu K; Gao HJ(高华健); Wei YJ
2010
发表期刊Nature
卷号464期号:7290页码:877-880
ISSN0028-0836
摘要In conventional metals, there is plenty of space for dislocations-line defects whose motion results in permanent material deformation-to multiply, so that the metal strengths are controlled by dislocation interactions with grain boundaries(1,2) and other obstacles(3,4). For nano-structured materials, in contrast, dislocation multiplication is severely confined by the nanometre-scale geometries so that continued plasticity can be expected to be source-controlled. Nano-grained polycrystalline materials were found to be strong but brittle(5-9), because both nucleation and motion of dislocations are effectively suppressed by the nanoscale crystallites. Here we report a dislocation-nucleation-controlled mechanism in nano-twinned metals(10,11) in which there are plenty of dislocation nucleation sites but dislocation motion is not confined. We show that dislocation nucleation governs the strength of such materials, resulting in their softening below a critical twin thickness. Large-scale molecular dynamics simulations and a kinetic theory of dislocation nucleation in nano-twinned metals show that there exists a transition in deformation mechanism, occurring at a critical twin-boundary spacing for which strength is maximized. At this point, the classical Hall-Petch type of strengthening due to dislocation pile-up and cutting through twin planes switches to a dislocation-nucleation-controlled softening mechanism with twin-boundary migration resulting from nucleation and motion of partial dislocations parallel to the twin planes. Most previous studies(12,13) did not consider a sufficient range of twin thickness and therefore missed this strength-softening regime. The simulations indicate that the critical twin-boundary spacing for the onset of softening in nano-twinned copper and the maximum strength depend on the grain size: the smaller the grain size, the smaller the critical twin-boundary spacing, and the higher the maximum strength of the material.
DOI10.1038/nature08929
URL查看原文
收录类别SCI
语种英语
WOS记录号WOS:000276397300034
关键词[WOS]MOLECULAR-DYNAMICS SIMULATION ; NANOCRYSTALLINE MATERIALS ; MECHANICAL-PROPERTIES ; NANOTWINNED COPPER ; DEFORMATION ; PLASTICITY ; NANOSCALE ; DUCTILITY ; CRYSTALS ; NICKEL
WOS研究方向Science & Technology - Other Topics
WOS类目Multidisciplinary Sciences
项目资助者NSF [DMR-0520651] ; Brown University [CMMI-0758535] ; NSFC [50621091, 50725103, 50890171] ; MOST of China [2005CB623604]
引用统计
被引频次:489[WOS]   [WOS记录]     [WOS相关记录]
文献类型期刊论文
条目标识符http://dspace.imech.ac.cn/handle/311007/43525
专题非线性力学国家重点实验室
通讯作者Wei YJ
推荐引用方式
GB/T 7714
Li XY,Wei YJ,Lu L,et al. Dislocation nucleation governed softening and maximum strength in nano-twinned metals[J]. Nature,2010,464(7290):877-880.
APA Li XY,魏宇杰,Lu L,Lu K,高华健,&Wei YJ.(2010).Dislocation nucleation governed softening and maximum strength in nano-twinned metals.Nature,464(7290),877-880.
MLA Li XY,et al."Dislocation nucleation governed softening and maximum strength in nano-twinned metals".Nature 464.7290(2010):877-880.
条目包含的文件 下载所有文件
文件名称/大小 文献类型 版本类型 开放类型 使用许可
102.pdf(1391KB) 开放获取--浏览 下载
个性服务
推荐该条目
保存到收藏夹
查看访问统计
导出为Endnote文件
谷歌学术
谷歌学术中相似的文章
[Li XY]的文章
[魏宇杰]的文章
[Lu L]的文章
百度学术
百度学术中相似的文章
[Li XY]的文章
[魏宇杰]的文章
[Lu L]的文章
必应学术
必应学术中相似的文章
[Li XY]的文章
[魏宇杰]的文章
[Lu L]的文章
相关权益政策
暂无数据
收藏/分享
文件名: 102.pdf
格式: Adobe PDF
此文件暂不支持浏览
所有评论 (0)
暂无评论
 

除非特别说明,本系统中所有内容都受版权保护,并保留所有权利。