The diffusivity of Si in Ti3Al with six compositions of 24.5at%Al to 34.7at%Al was invesitigated by using the diffusion couples (Ti 3Al/Ti3Al-X; X=0.5at%Si) at 1248-1423K. The diffusion coefficients of Si, DSi'S, were smaller than those of Ti and Al by a factor of 1/20 at most. The DSi'S slightly depended on Al concentration. The activation energies of Si diffusion, QSi'S, were in the range of 450-550kJ/mol, and they tended to decreace with increasing Al concentration. From the comparison of the Q's evaluated for various diffusion mechanisms and the experimantal QSi'S it was indicated that Si atoms preferably substitute for Al-site in Ti3Al with D019-type ordered structure, and the Si diffusion is dominated by the sublattice antisite diffusion (SAD) mechanism in which Si atoms diffuse via Ti-sublattice in the form of antistructure-like atoms as well as the Al diffusion.
|ジャーナル||Defect and Diffusion Forum|
|出版ステータス||Published - 2005|
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics