Multiscale description of dislocation induced nano-hydrides
Multiscale description of dislocation induced nano-hydrides
复制标题
DOI：
10.1016/j.actamat.2015.01.057
复制
发表时间：
2015-05
期刊：
影响因子：
9.4
通讯作者：
G. Leyson;B. Grabowski;J. Neugebauer
中科院分区：
文献类型：
--
作者：
G. Leyson;B. Grabowski;J. Neugebauer
用多尺度方法研究了氢与核的相互作用和边缘位错的应变场。因此，我们开发了一种具有全原子分辨率的热力学和分析相结合的模型，可以量化位错核心周围的局部氢浓度作为温度和氢化学势的函数。该模型将氢原子-氢原子相互作用和位错核心结构等原子计算信息作为输入，并忠实地再现了计算成本更高的全原子方法的结果，该方法将嵌入式原子方法与蒙特卡罗模拟相结合。通过氢化物尺寸随温度和体积氢浓度的参数化研究，预测了纳米氢化物形成的开始和氢增强局部塑性（HELP）的激活。研究揭示了氢化物形成和非氢化物形成之间的急剧转变。这两种状态之间的跃迁对应于与体系的纳米氢化物核相关的临界氢化学势μ H c。
The interaction of hydrogen with the core and the strain field of edge dislocations is studied using a multiscale approach. We have therefore developed a combined thermodynamic and analytical model with full atomistic resolution that allows to quantify the local hydrogen concentration around the dislocation core as a function of temperature and hydrogen chemical potential. This model takes, as input, information from atomistic calculations, such as hydrogen–hydrogen interaction and the dislocation core structure, and faithfully reproduces results from a computationally much more expensive fully atomistic approach that combines the Embedded Atom Method with Monte Carlo simulations. The onset of nano-hydride formation and with it the activation of hydrogen enhanced local plasticity (HELP) is predicted through a parametric study of the hydride size as a function of temperature and bulk hydrogen concentration. The study reveals a sharp transition between hydride forming and non-hydride forming regimes. The transition between these two regimes corresponds to a critical hydrogen chemical potential μ H c related to the nano-hydride nucleus of the system.