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International Journal for Multiscale Computational Engineering
IF: 1.016 5-Year IF: 1.194 SJR: 0.554 SNIP: 0.68 CiteScore™: 1.18

ISSN Print: 1543-1649
ISSN Online: 1940-4352

International Journal for Multiscale Computational Engineering

DOI: 10.1615/IntJMultCompEng.2012003177
pages 59-69

A STUDY OF DISLOCATION CLIMB MODEL BASED ON COUPLING THE VACANCY DIFFUSION THEORY WITH 3D DISCRETE DISLOCATION DYNAMICS

Yuan Gao
Applied Mechanics Laboratory, School of Aerospace, Tsinghua University, Beijing 100084 China
Zhuo Zhuang
Failure Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084
X. C. You
Failure Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China

ABSTRACT

Dislocation climb plays a vital role in the plastic behavior of crystals at high temperatures. In order to reveal the intrinsic mechanism of climb and its effect to plasticity, a new dislocation climb model is firstly developed based on the incorporation the diffusion theory by both bulk diffusion and pipe diffusion in a three-dimensional Discrete Dislocation Dynamics (3D-DDD) simulation, which is considered to be more physical and widely applicable. Using our model the shrinkage processes of a single prismatic loop and prismatic loops group was simulated. It is concluded that the climb rate is not directly determined by mechanical climb force as believed in classical theories, but by the gradient of the vacancy concentration around (bulk diffusion) and along (pipe diffusion) the dislocation line. Loop coarsening process was also simulated and the three pronounced evolving stages of the loop radii and the average vacancy concentrations in crystal were reproduced.