Crack growth versus blunting in nanocrystalline metals with extremely small grain size
Crack growth versus blunting in nanocrystalline metals with extremely small grain size
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DOI：
10.1016/j.jmps.2008.10.011
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发表时间：
2009-02-01
影响因子：
5.3
通讯作者：
Yang, Wei
中科院分区：
文献类型：
--
作者：
Yang, Fan;Yang, Wei
采用结构演化的方法模拟了纳米晶金属的断裂过程。采用二维格式研究了含边缘裂纹的纳米晶样品中裂纹扩展与钝化之间的竞争。该方案耦合了晶界机制引起的蠕变变形和沿晶裂纹扩展。探讨了材料特性、初始构型和外加载荷对结构的影响。无论是扩散迁移率的提高，还是晶界损伤的威慑，都会使裂纹钝化并减缓其生长，反之亦然。模拟结果与Yang和Yang [2008]的分析预测一致。纳米晶金属的脆韧转变。Int.J.SolidsStruct.45，3897-3907]。位错活动的抑制后，它被验证，纳米晶体的脆性与韧性转变是由晶界主导的蠕变与晶界脱粘的发展控制。进一步的模拟发现，减小晶粒尺寸或增加晶粒尺寸的分散性将钝化生长的裂纹。(c)2008爱思唯尔有限公司保留所有权利。
Fracture of nanocrystalline metals with extremely small grain size is simulated in this paper by structural evolution. Two-dimensional scheme is formulated to study the competition between crack growth and blunting in nanocrystalline samples with edge cracks. The scheme couples the creep deformation induced by grain boundary (GB) mechanisms and the intergranular crack growth. The effects of material properties, initial configurations and applied loads are explored. Either the enhancement in diffusion mobility, or the deterrence in the grain boundary damage, would blunt the crack and decelerate its growth, and vice versa. The simulations agree with the analytical predictions as modified from that of Yang and Yang [2008. Brittle versus ductile transition of nanocrystalline metal. Int. J. Solids Struct. 45, 3897-3907]. Upon the suppression of dislocation activities, it is validated that the brittle versus ductile transition of nanocrystals is controlled by the development of grain boundary-dominated creep versus grain boundary decohesion. Further simulations found that either decreasing the grain sizes or increasing the dispersion of grain sizes would blunt the growing cracks. (c) 2008 Elsevier Ltd. All rights reserved.