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Incorporating point defect generation due to jog formation into the vector density-based continuum dislocation dynamics approach
Journal of the Mechanics and Physics of Solids ( IF 5.0 ) Pub Date : 2021-08-12 , DOI: 10.1016/j.jmps.2021.104609
Peng Lin 1 , Vignesh Vivekanandan 1 , Benjamin Anglin 2 , Clint Geller 2 , Anter El-Azab 1
Affiliation  

During plastic deformation of crystalline materials, point defects such as vacancies and interstitials are generated by jogs on moving dislocations. A detailed model for jog formation and transport during plastic deformation was developed within the vector density-based continuum dislocation dynamics framework (Lin and El-Azab, 2020; Xia and El-Azab, 2015). As a part of this model, point defect generation associated with jog transport was formulated in terms of the volume change due to the non-conservative motion of jogs. Balance equations for the vacancies and interstitials including their rate of generation due to jog transport were also formulated. A two-way coupling between point defects and dislocation dynamics was then completed by including the stress contributed by the eigen-strain of point defects. A jog drag stress was further introduced into the mobility law of dislocations to account for the energy dissipation during point defects generation. A number of test problems and a fully coupled simulation of dislocation dynamics and point defects generation and diffusion were performed. The results show that there is an asymmetry of vacancy and interstitial generation due to the different formation energies of the two types of defects. The results also show that a higher hardening rate and a higher dislocation density are obtained when the point defect generation mechanism is coupled to dislocation dynamics.



中文翻译:

将由于点动形成而产生的点缺陷纳入基于矢量密度的连续位错动力学方法

在晶体材料的塑性变形过程中,移动位错上的点动会产生空位和间隙等点缺陷。在基于矢量密度的连续位错动力学框架(Lin 和 El-Azab,2020 年;Xia 和 El-Azab,2015 年)内开发了塑性变形过程中慢跑形成和传输的详细模型。作为该模型的一部分,与慢跑传输相关的点缺陷生成是根据慢跑的非保守运动引起的体积变化来制定的。还制定了空位和间隙的平衡方程,包括由于慢跑运输而产生的速率。然后通过包括点缺陷的本征应变贡献的应力来完成点缺陷和位错动力学之间的双向耦合。在位错迁移定律中进一步引入了缓动拖曳应力,以解释点缺陷生成过程中的能量耗散。执行了许多测试问题以及位错动力学和点缺陷生成和扩散的完全耦合模拟。结果表明,由于两种缺陷的形成能不同,空位和填隙的产生存在不对称性。结果还表明,当点缺陷产生机制与位错动力学耦合时,可以获得更高的硬化速率和更高的位错密度。执行了许多测试问题以及位错动力学和点缺陷生成和扩散的完全耦合模拟。结果表明,由于两种缺陷的形成能不同,空位和填隙的产生存在不对称性。结果还表明,当点缺陷产生机制与位错动力学耦合时,可以获得更高的硬化速率和更高的位错密度。执行了许多测试问题以及位错动力学和点缺陷生成和扩散的完全耦合模拟。结果表明,由于两种缺陷的形成能不同,空位和填隙的产生存在不对称性。结果还表明,当点缺陷产生机制与位错动力学耦合时,可以获得更高的硬化速率和更高的位错密度。

更新日期:2021-08-26
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