The disconnection mechanism of coupled migration and shear at grain boundaries

被引：115
作者：
Khater, H. A. [1 ]
Serra, A. [1 ]
Pond, R. C. [2 ]
Hirth, J. P.
机构：
[1] Univ Politecn Catalunya UPC, Dept Matemat Applicada 3, Barcelona 08034, Spain
[2] Univ Exeter, Coll Engn Math & Phys Sci, Exeter EX4 4QF, Devon, England
来源：
ACTA MATERIALIA | 2012年 / 60卷 / 05期
关键词：
Grain boundary shear; Grain boundary migration; Grain boundary dislocations; Disconnections; TWINNING DISLOCATIONS; COMPUTER-SIMULATION; MOTION; DEFECTS; FORCES; FIELDS; MODEL;
D O I：
10.1016/j.actamat.2012.01.001
中图分类号：
T [工业技术];
学科分类号：
08 ;
摘要：
The mechanism of coupled migration and shear is studied in a range of [0001] tilt boundaries in hexagonal close-packed metal using atomic-scale computer simulation. Symmetrical tilt boundaries spanning the low- and high-angle regimes and comprising regular arrays of grain boundary dislocations are simulated. For each misorientation, theta, the perfect boundary (pristine) is investigated as well as one containing a disconnection. Both types of structures are subjected to incremental applied strains to determine the stress that produces coupled migration and shear. The stress for motion in the pristine case, entailing nucleation, is higher than the Peierls stress for motion when disconnections are present. We conclude that the applied stresses in our simulations exert a Peach-Koehler force on pre-existing disconnections, thereby providing a feasible mechanism with a well-defined driving force that produces coupled migration and shear. This mechanism is feasible for the lower-angle boundaries studied, and facile for the high-angle cases. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
引用
收藏
页码：2007 / 2020
页数：14
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