(1. 南京航空航天大学材料科学与技术学院，南京 210016；
2. 中航工业金城南京机电液压工程研究中心，南京 211106)
摘 要: 采用基于密度泛函理论的第一性原理计算H原子在Ti晶格中占据不同位置的体系能量。通过对体系能量变化的分析，探求H原子在Ti晶格中的扩散路径和能量势垒，分析室温下H原子在不同Ti晶体结构中的扩散行为与难易程度。结果表明：H原子在α-Ti晶格中从八面体间隙与四面体间隙共用面扩散、迁移，而在β-Ti晶格中则从两相邻四面体间隙共用面扩散、迁移。H原子在β-Ti晶格中扩散迁移所需克服的能量势垒比在α-Ti晶格中扩散迁移所需克服的能量势垒小、更容易进行扩散。在α+β钛合金中，处于β相四面体间隙中的H原子在扩散过程中将起到主导作用。
关键字: Ti晶体；H原子扩散；第一性原理；体系能量；间隙
（1. College of Materials Science and Technology,
Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;
2. Aviation Industry Corporation of China Jincheng Nanjing Electrical and
Hydraulic Engineering Research Center, Nanjing 211106, China）
Abstract:The first-principles calculation was carried out on the Ti-H supercells based on the density functional theory. The system energy was obtained in various Ti-H supercells. The hydrogen diffusion pathway and the energy barrier were investigated through analyzing the energy change of titanium crystals with the H atom at different positions. The difficulty degree of the hydrogen diffusion was analyzed at the room temperature. The results show that H atoms diffuse across the share surfaces of the octahedral and tetrahedral interstitials and from the octahedral interstitials to the tetrahedral ones in the α-Ti crystals. H atoms diffuse across the adjacent tetrahedral interstitials sharing surfaces and from one tetrahedral interstitial to the other in the β-Ti crystals. The energy barrier needed to be overcome for the H diffusion in the β-Ti crystals is lower than that in the α-Ti crystals. H atoms occupying the tetrahedral interstitials in the β-Ti will play a leading role in the α+β titanium alloy during the diffusion process.
Key words: Ti crystal; H atom diffusion; first-principles; system energy; interstitials
