γ-Fe中氢扩散行为的第一性原理研究
First-principles study on hydrogen diffusion behavior in γ-Fe
汤伟杰 1王红英 2李志军1
作者信息
- 1. 深圳职业技术学院工业训练中心,深圳 518055
- 2. 深圳职业技术学院机电工程学院,深圳 518055
- 折叠
摘要
不锈钢中氢脆问题一直是研究者们关注热点,然而至今为止,对于钢中合金元素及空位与H原子之间的作用机理依然不清晰.采用第一性原理方法研究了 H原子在不同体系下γ-Fe(Fe8H、Fe7Cr/MoH、Fe7H)的扩散激活能、扩散系数以及扩散过渡态,对比了 H原子在不同体系γ-Fe中的扩散难易程度,并从电子结构层次解释其相互作用.研究结果表明,空位的存在会改变H原子在γ-Fe中的扩散路径.在含空位的晶胞中H原子稳定存在于空位附近的近四面体间隙中,并沿空位附近的四面体间隙或八面体到四面体间隙路径扩散.γ-Fe中空位对H原子的影响是局域性的,一方面是捕获H原子的陷阱;另一方面降低了 H原子的扩散激活能,促进H原子的扩散.而Cr/Mo的掺杂会降低空位对H原子的束缚,也会抑制H原子的扩散.
Abstract
The problem of hydrogen embrittlement in stainless steel has always been a hot topic for researchers.However,until now,the mechanism of interaction between alloying elements and vacancy and H atom in steel re-mains unclear.The diffusion activation energies,diffusion coefficients and diffusion transition states of y-Fe(Fe8H,Fe7Cr/MoH,Fe7H)of H atom in different systems are studied by using first-principles method.The diffusion difficulty of γ-Fe atoms in different systems are compared,and the interactions are explained from the electronic structure level.The results show that the existence of vacancy changes the diffusion path of H atom inγ-Fe.In the cell with vacancy,H atom stably exists in the near tetrahedral gap near the vacancy and diffuses along the tetrahedral gap near the vacancy or the octahedral to tetrahedral gap path.The effect of vacancy on H atom in γ-Fe is local.On the one hand,it is a trap to capture H atom.On the other hand,the diffusion activa-tion energy of H atom is reduced and the diffusion of H atom is promoted.However,the doping of Cr/Mo can re-duce the binding of vacancy to H atom and inhibit the diffusion of H atom.
关键词
第一性原理/氢扩散/γ-Fe/扩散激活能/电子结构Key words
First principles/Hydrogen diffusion/γ-Fe/Diffusion activation energy/Electronic structures引用本文复制引用
基金项目
深圳市科技研发资金(JCYJ20190809150001747)
出版年
2024
国家科技期刊平台
NSTL
维普
万方数据