Diffusivities and Atomic Mobilities in the bcc Phase of the Ti-Al-Fe System
Author of the article:TONG Jianbo1, WANG Xiangdong2,3, NIE Jingjing2,3, HUANG Yi2,3, BAI Weimin2,3, CHENG Jun4
Author's Workplace：1. Aviation Key Laboratory of Science and Technology on Advanced Titanium Alloys, AECC Beijing Institute ofAeronautical Materials, Beijing 100095; 2. School of Materials Science and Engineering, Xiangtan University, Xiangtan411105, China; 3. Key Laboratory of Materials Design and Preparation Technology of Hunan Province Xiangtan University,Xiangtan 411105, China; 4. Northwest Institute for Nonferrous Metal Research, Shaanxi Key Laboratory of Biomedical MetalMaterials, Xi'an 710016, China
Key Words：atomic mobility; diffusion coefficient; Ti-Al-Fe alloy; HitDIC; CALPHAD
Abstract：
The diffusion behavior of elements in titanium alloys is crucial to the preparation, processing and service ofthese materials. In this paper, the diffusion behavior of alloying elements in the bcc phase of a Ti-Al-Fe system at 1 000and 1 100 ℃ was studied. Eight pairs of bcc-Ti-Al-Fe single-phase alloy diffusion couples were prepared and annealedat 1 000 and 1 100 ℃. The composition-distance profiles of these diffusion couples were determined by using EPMA. Anatomic mobility database of the bcc phase in the Ti-Al-Fe system was established by the CALPHAD (calculation of phasediagrams) approach based on the obtained diffusion coefficients. In the optimization process, HitDIC software was used toobtain the atomic mobility parameters and interdiffusion coefficient. Using the obtained atomic mobility parameters, thediffusion processes of the diffusion couples were simulated. The calculated results are consistent with the experimentaldiffusion characteristics (interdiffusion, composition-distance profiles and diffusion paths), indicating the accuracy of thedatabase. This research is highly important for further understanding the microstructure evolution and properties of titaniumalloys.
