Strengthening mechanism in micro-polycrystals with penetrable grain boundaries by discrete dislocation dynamics simulation and Hall-Petch effect
Strengthening mechanism in micro-polycrystals with penetrable grain boundaries by discrete dislocation dynamics simulation and Hall-Petch effect
复制标题
通过离散位错动力学模拟和 Hall-Petch 效应研究具有可穿透晶界的微多晶的强化机制
DOI：
10.1016/j.commatsci.2009.05.021
复制
发表时间：
2009-10-01
影响因子：
3.3
通讯作者：
Ouyang, Chaojun
中科院分区：
文献类型：
--
作者：
Li, Zhenhuan;Hou, Chuantao;Ouyang, Chaojun
晶粒尺寸对微多晶屈服应力和流动强度的影响与晶界（GB）对位错的穿透性密切相关。为了模拟位错跨晶界的传输，Giessen 和 Needleman (1995) 提出了位错-晶界穿透模型，并将其集成到二维离散位错动力学 (DDD) 框架中。通过这种扩展的DDD技术。对微多晶中的Hall-Petch效应及其强化机制进行了计算研究，主要关注以前未充分考虑的跨晶界位错传输的显着影响。结果表明，Hall-Petch 型关系仍然适用，但强烈依赖于位错的晶界穿透性，尤其是大偏移应变下的流动强度。初始屈服应力和流变应力的Hall-Petch晶粒尺寸敏感指数n的拟合值与已发表文献中的实验测量数据基本一致。 (C) 2009 Elsevier B.V. 保留所有权利。
The grain-size effect on the yield stress and the flow strength in micro-polycrystals relates closely to the penetrability of grain boundary (GB) to dislocations. To simulate the dislocation transmission across grain boundary, a dislocation-grain boundary penetration model is proposed and then integrated into the two-dimensional discrete dislocation dynamics (DDD) framework by Giessen and Needleman (1995). By this extended DDD technology. the Hall-Petch effect in micro-polycrystals and the strengthening mechanism are computationally studied, with the main focus on the significant influence of the dislocation transmission across grain boundary that is not fully considered formerly. Results indicate that the Hall-Petch type relation is still applicable, but depends strongly on the GB-penetrability to dislocations, especially for the flow strength at large offset strains. The fitting values of Hall-Petch grain-size sensitive exponents n for initial yield stress and flow stress basically agree with experimentally measured data in published literatures. (C) 2009 Elsevier B.V. All rights reserved.