期刊
ACTA MATERIALIA
卷 60, 期 6-7, 页码 2959-2972出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.actamat.2012.02.002
关键词
In situ transmission electron microscopy; Molecular dynamics; Nanoscale twins; Crack bridging; Dislocations
资金
- NSF through MRSEC at Brown University [DMR-0520651]
- NSF [CMMI-0758535]
- National Research Council of Science & Technology (NST), Republic of Korea [PNK2880] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
In situ tensile experiments in a transmission electron microscope revealed that micro-cracks in ultrafine grained, free-standing, thin copper foils containing nanoscale twins initiated in matrix domains separated by the twins and then arrested at twin boundaries as twin boundary sliding proceeded. The adjacent microcracks eventually coalesced through shear failure of the bridging twins. To investigate the atomic mechanism of this rarely seen nanoscale crack bridging behavior, molecular dynamics simulations were performed to show that during crack propagation twin boundaries are impinged upon by numerous dislocations from the plastically deforming matrix. These dislocations react at the interface and evolve into substantially impenetrable dislocation walls that strongly confine crack nucleation and resist crack propagation, leading to the experimentally observed crack bridging behavior. The present results raise an approach to significantly toughening polycrystalline thin films by incorporating nanoscale twin structures into individual grains that serve as crack bridging ligaments. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据