Brittle versus ductile transition of nanocrystalline metals

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:45

Article

Yang, Fan¹  Yang, Wei^1,2 

[1] Tsinghua Univ, Dept Engn Mech, Beijing 100084, Peoples R China

[2] Zhejiang Univ, Hangzhou 310058, Peoples R China

关键词: nanocrystalline metals;    brittle versus ductile transition;    grain boundary creep;    crack propagation;   

DOI  :  10.1016/j.ijsolstr.2007.12.018

来源: Elsevier

【 摘 要 】

The brittle versus ductile transition for conventional metals is dictated by the competition between dislocation emission and cleavage. For nanocrystalline metals with grain size below 25 nm, however, dislocation activities are suppressed and the classic theory fails to apply. In this paper, one of the competing mechanisms that control the brittle versus ductile transition of nanocrystalline metals is found to be the grain boundary dominated creep deformation versus the grain boundary decohesion. A model is proposed to quantify the crack propagation in nanocrystalline metals. The effects of material properties, initial configuration and applied loads on the property of crack propagation are addressed. It is concluded that either the increases in the initial crack length, the applied load and the grain boundary damage, or the deterrence in creep deformation, accelerate the crack propagation, and vice versa. (C) 2008 Elsevier Ltd. All rights reserved.

【 授权许可】

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