Qin Jiayao, Liu Zhigao, Zhao Wei, Wang Dianhui, Zhang Yanli, Zhong Yan, Zhang Xiaohui, Wang Zhongmin, Hu Chaohao, Liu Jiangwen
Guangxi Key Laboratory of Information Materials, School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin 541004, China.
Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China.
Materials (Basel). 2021 May 17;14(10):2603. doi: 10.3390/ma14102603.
Hydrogen embrittlement causes deterioration of materials used in metal-hydrogen systems. Alloying is a good option for overcoming this issue. In the present work, first-principles calculations were performed to systematically study the effects of adding Ni on the stability, dissolution, trapping, and diffusion behaviour of interstitial/vacancy H atoms of pure V. The results of lattice dynamics and solution energy analyses showed that the V-Ni solid solutions are dynamically and thermodynamically stable, and adding Ni to pure V can reduce the structural stability of various VH phases and enhance their resistance to H embrittlement. H atoms preferentially occupy the characteristic tetrahedral interstitial site (TIS) and the octahedral interstitial site (OIS), which are composed by different metal atoms, and rapidly diffuse along both the energetically favourable TIS → TIS and OIS → OIS paths. The trapping energy of monovacancy H atoms revealed that Ni addition could help minimise the H trapping ability of the vacancies and suppress the retention of H in V. Monovacancy defects block the diffusion of H atoms more than the interstitials, as determined from the calculated H-diffusion barrier energy data, whereas Ni doping contributes negligibly toward improving the H-diffusion coefficient.
氢脆会导致金属 - 氢系统中使用的材料性能劣化。合金化是克服这一问题的良好选择。在本工作中，进行了第一性原理计算，以系统研究添加镍对纯钒中间隙/空位氢原子的稳定性、溶解、捕获和扩散行为的影响。晶格动力学和溶解能分析结果表明，钒 - 镍固溶体在动力学和热力学上是稳定的，向纯钒中添加镍可以降低各种VH相的结构稳定性并增强其抗氢脆能力。氢原子优先占据由不同金属原子组成的特征四面体间隙位置（TIS）和八面体间隙位置（OIS），并沿着能量有利的TIS→TIS和OIS→OIS路径快速扩散。单空位氢原子的捕获能表明，添加镍有助于最小化空位的氢捕获能力并抑制氢在钒中的滞留。根据计算得到的氢扩散势垒能量数据，单空位缺陷比间隙原子对氢原子扩散的阻碍更大，而镍掺杂对提高氢扩散系数的贡献可忽略不计。
