Solute hydrogen effects on plastic deformation mechanisms of alpha-Fe with twist grain boundary
Solute hydrogen effects on plastic deformation mechanisms of alpha-Fe with twist grain boundary
复制标题
溶质氢对扭转晶界α-Fe塑性变形机制的影响
DOI：
10.1016/j.ijhydene.2018.04.133
复制
发表时间：
2018
影响因子：
7.2
通讯作者：
Huang Minsheng
中科院分区：
文献类型：
--
作者：
Zhu Yaxin;Li Zhenhuan;Huang Minsheng
使用分子动力学模型仔细研究了含有不同角度扭曲晶界 (TGB) 的 α-Fe 扭曲双晶 (TBC) 的变形机制，特别关注溶质氢如何影响它们。结果表明，热障涂层存在三种主要变形，即位错滑移主导机制、缠绕主导机制、位错滑移和缠绕共同主导机制，这取决于扭转角和加载方向。在位错滑移为主的热障涂层中，溶质氢增加了位错成核强度、位错迁移率和位错密度，由于溶质氢原子与位错的频繁相互作用，进一步增加了空位浓度。在位错滑移和孪晶共同主导的热障涂层中，随着拉伸应变的增加，溶质氢对位错密度的增加和孪晶分数的减少的影响较弱。然而，在以孪晶为主的热障涂层中，溶质氢有助于变形孪晶，但不会显着增加空位浓度。因此，孪生变形似乎有利于抵抗氢脆（HE）。这些知识有助于我们理解HE机理并开发新型抗氢高强材料。
The deformation mechanisms in the α-Fe twist bi-crystals (TBCs) containing differently angled twist grain boundaries (TGBs) are investigated carefully using the molecular dynamics modeling, with especial concerns on how solute hydrogen affects them. The results show that there are three main deformations in the TBCs, i.e. the dislocation glide-dominated mechanism, the twining-dominated mechanism, the dislocation glide and twining co-dominated mechanism, depending upon both the twist angle and the loading direction. In the dislocation glide-dominated TBCs, solute hydrogen increases the dislocation nucleation strength, dislocation mobility and dislocation density, further increases the vacancies concentration due to frequent interactions of solute hydrogen atoms with dislocations. In the dislocation glide and twining co-dominated TBCs, the solute hydrogen has weaker effect on the increase of dislocations density and the decrease of twins fraction with increasing tensile strain. However, in the twining-dominated TBCs, solute hydrogen assists the deformation twinning but doesn't increase significantly the vacancies concentration. So, it seems that twinning deformation is beneficial to resist hydrogen embrittlement (HE). These knowledge is helpful for us to understand the HE mechanism and develop new hydrogen-resistant high-strength materials.