Evidence of 'microscopic bubbles' and a new diffusion mechanism for amorphous alloys

Abstract

Simulation of the diffusion mechanism in amorphous alloys is carried out using three statistical relaxation models Fe80B20 with 105 atoms. We found for the first time that the simulated models contain a large number of vacancy bubbles, which could be a diffusion vehicle such as a vacancy, as in the case of diffusion in a crystal. The numbers of these vacancy bubbles vary from 2.8 × 10-3 to 1.245 × 10-2 per atom depending on the relaxation degree. Diffusion coefficients have been calculated via the vacancy bubbles and they are very consistent with experiment. The relaxation effect is also studied and interpreted as a result of vacancy-bubble annihilation during thermal annealing. © 2010 IOP Publishing Ltd.