Tracer diffusion in amorphous solid was studied by mean of 𝑛𝐵-bubble statistic. The 𝑛𝐵-bubble was defined as a group of atoms around a spherical void and large bubble that represented a structural defect which could be eliminated under thermal annealing. It was found that amorphous alloys such as Co𝑥B100-𝑥 (𝑥 = 90, 81.5 and 70) and Fe80P20 suffer from a large number of vacancy bubbles which function like diffusion vehicle. The concentration of vacancy bubble weakly depended upon temperature, but essentially upon the relaxation degree of considered sample. The diffusion coefficient estimated for proposed mechanism via vacancy bubbles was in a reasonable agreement with experiment for actual amorphous alloys. The relaxation effect for tracer diffusion in amorphous alloys was interpreted by the elimination of vacancy bubbles under thermal annealing.

Tracer Diffusion Mechanism in Amorphous Solids. P.K.Hung, P.H.Kien, H.V.Hue: Journal of Metallurgy, 2011, 861373