摘要
二维离散位错动力学模型是研究微观尺度复杂载荷条件下材料的塑性变形行为的有效手段之一,在现有模型结构基础上,对离散位错动力学方法的3个重要进展进行了综述。首先介绍了二维离散位错动力学基于叠加法原理的算法框架,各向异性弹性场的引入有效扩展了离散位错动力学模型在多晶多相材料中的应用。其次系统论述了模型中与率敏感性相关的位错运动机制,通过引入位错在热激活效应下通过钉扎障碍的运动机制,实现了对低应变速率区间的率敏感性的预测。最后,对位错与界面相互作用进行了探讨,并结合模型计算方法的发展和在实际问题中的应用进行分析,以期为金属塑性变形机理的研究提供理论参考。
Two-dimensional discrete dislocation dynamics( 2 D-DDD) model is one of the effective methods to investigate the plastic deformation behavior of materials under complex loading conditions at micro scale. Based on the existent modelling framework,three main developments regarding the DDD methodology were reviewed. The algorithm framework based on superposition principle in 2 D-DDD was first introduced. The introduction of anisotropic elastic fields effectively extends the applications of discrete dislocation dynamics model in polycrystalline and multi-phase materials. Then the dislocation escape mechanisms related to the strain rate sensitivity were discussed systematically. By introducing the thermally activated dislocation escape mechanism from pinning barriers,the prediction of strain rate sensitivity at low strain rate regions was realized. Finally,the interactions between dislocations and interfaces were discussed. The developments in the modelling methodology together with the applications to solve real-world problems were analyzed,aiming at providing theoretical guidance for the research in the plastic deformation mechanisms of metals.
作者
郑泽邦
旷野
詹梅
ZHENG Ze-bang;KUANG Ye;ZHAN Mei(Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment,School of Materials Science and Engineering,Northwestern Polytechnical University,Xi'an 710072,China)
出处
《塑性工程学报》
CAS
CSCD
北大核心
2020年第7期13-20,共8页
Journal of Plasticity Engineering
基金
国家自然科学基金资助项目(91860130,U1910213)。
关键词
离散位错动力学
叠加法原理
热激活
率敏感性
尺寸效应
discrete dislocation dynamics
superposition principle
thermal activation
strain rate sensitivity
size effect
