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

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.