中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 29 No. 3 March 2019 |
（1. School of Materials Science and Engineering, Shenyang Aerospace University, Shenyang 110136, China;
2. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China）
Abstract:In order to understand the evolution of oxygen-rich layer (ORL) on titanium alloys, the near α titanium alloy TA15 and α+β type titanium alloy TC4 were thermally exposed in air at 850 °C to evaluate the effect of α phase content on formation and evolution of ORL, and the stability and diffusion of oxygen in α- and β-Ti were investigated by first principles calculations to reveal the oxygen diffusion rate. TA15 with more α phases has a higher diffusion coefficient of ORL evolution than TC4, resulting in forming thicker ORL on TA15 under the same thermal exposure condition. The first principles calculations indicate that octahedral interstice of α-Ti is the most stable site for oxygen atom. The nearest neighbor diffusion between octahedral interstices along the [0001] direction in α-Ti presenting the lowest activation energy is the most favorable oxygen diffusion mechanism in α- and β-Ti.
Key words: oxygen-rich layer; titanium alloys; oxygen diffusion
