期刊
INTERNATIONAL JOURNAL OF PLASTICITY
卷 101, 期 -, 页码 170-187出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.ijplas.2017.11.002
关键词
Dislocations; Stress relaxation; Mobility law; Molecular dynamics
资金
- Ministry of Education and Science of the Russian Federation [3.2510.2017/PP]
- President of the Russian Federation [MD-7481.2016.1]
- Act 211 Government of the Russian Federation [02.A03.21.0011]
On the basis of theoretical consideration and analysis of molecular dynamic (MD) simulation data, we show that the dislocation motion is determined by the stress field in its local environment. These stresses differ from the values averaged over even such tiny microscopic regions, which are usually used in MD study of dislocation motion. As a result, the slip velocity of dislocations can remain virtually constant with a gradual decrease in the average stresses in the calculation area. When a dislocation enters the trace of the previous dislocation, that is, into a region plastically relaxed by the slip of the previous dislocation, its velocity, on the contrary, decreases sharply, even if the average stresses in the region vary slightly. The revealed complex behavior leads to variable final average stress after the completion of the movement of dislocations; the average stress sometimes even changes its sign in the course of plastic relaxation. All these features can influence the response of the dislocation system to mechanical loading. Therefore, the action of the local stresses should be taken into account when analyzing the MD results, in the development of continuum models of plasticity, as well as in discrete dislocation dynamics. A dislocation motion equation is proposed with accounting of local stresses, and the constants for the edge dislocation in Al are determined by comparison with the results of MD simulations, An asymptotic solution of this equation is proposed, which can be used in the numerical solution of the equations of continuum dislocation plasticity. Alternative dependencies of the drag force on the dislocation velocity are analyzed; it is shown that they describe the results of MD Simulations worse than the equation proposed by us.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据