期刊
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
卷 16, 期 -, 页码 1904-1918出版社
ELSEVIER
DOI: 10.1016/j.jmrt.2021.12.107
关键词
Bauschinger effect; Discrete dislocation plasticity; Rate sensitivity; Thermal activation; Size effect
资金
- National Natural Science Foundation of China [91860130, U1910213, U1937203]
- Natural Science Basic Research Plan in Shaanxi Province of China [2020JQ-166]
This study employs a two-dimensional discrete dislocation plasticity model to investigate the effect of strain rate asymmetry on the Bauschinger effect. The results show that increasing the source density enhances the rate dependence of the Bauschinger effect in obstacle-free specimens, while obstacles reduce the rate dependence. In low strain rate regimes, grain boundaries and obstacles with high activation energies enhance the rate dependence of the Bauschinger effect, suggesting that decreasing the grain size or reducing the activation energy can strengthen the rate dependence.
A two-dimensional discrete dislocation plasticity model was used to examine the role of strain rate asymmetry on the Bauschinger effect (BE). A simple single crystal single slip plane model was used first to investigate stress-strain response within high strain rate regimes where the rate sensitivity is mainly governed by dislocation nucleation and the free-flight of dislocations. Both the yield strength and the BE of the specimen showed a strong correlation to the forward and reverse deformation rate. Simulations were also carried out on a single crystal with multiple slip systems. The effect of source and obstacle density on the BE and its rate dependence was investigated. We find that the rate dependence of the BE is enhanced by increasing the source density in obstacle-free specimens and is reduced by obstacles when they are present. At low strain rates, where thermally-activated dislocation escape from obstacles becomes the predominant rate controlling mechanism, the BE of single crystals is only affected by strain rates if the activation energy is low. Grain boundaries in polycrystalline specimens and obstacles with high activation energies act as barriers to dislocation motion, suggesting that the rate dependence under low strain rate regimes is enhanced by decreasing the grain size or reducing the activation energy associated with dislocation escape from obstacles. The effect mechanisms of strain rate asymmetry on the BE can be fundamentally crucial for multiple industrial applications, including lifetime assessments of aero-engine disks, zirconium cladding of nuclear reactor and the spring-back prediction of metal forming. (c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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