Diffusion behavior of Ni in Zr₄₈Cu₃₆Ag₈Al₈ bulk metallic glass within supercooled liquid region

Abstract Diffusion behavior of Ni in Zr₄₈Cu₃₆Ag₈Al₈ metallic glass was investigated in the temperature range of 683-723 K by secondary ion mass spectrum (SIMS) and transmission electron microscope (TEM). The diffusivity of Ni in Zr₄₈Cu₃₆Ag₈Al₈ is reasonably fitted by a single Arrhenius relation with small effective activation energy. The diffusivity of Ni in Zr₄₈Cu₃₆Ag₈Al₈ is an instantaneous function of annealing time in the supercooled liquid region. In addition, a large number of nano-crystals are detected near the interface of Ni-Zr₄₈Cu₃₆Ag₈Al₈ diffusion couple, and its width is broader than the Ni diffusion depth determined by SIMS. The results indicate that atomic inter-diffusion is an important factor to promote the formation of nano-crystals within the diffusion zone.