Zn Diffusion in Binary Base of Light Mg-AI Alloys

摘要

Heterodiffusion of ~(65)Zn in Mg, Mg - x Al (x = 1.77, 3.9 and 9 wt.% Al) and in the commercial AZ91 alloy was studied in the temperature interval 498 - 848 K by serial sectioning and residual activity methods. The concentration and temperature dependence of Zn bulk diffusion coefficient D is described by the relation D = exp (0.1×c_(Al) - 9.16) x exp (-125.8 kJ mol~(-1)/RT) m~2 s~(-1) (cM - concentration of Al in wt.%). Zn grain boundary diffusivity P = s δD_b (s - segregation factor, δ - grain boundary width and D_b - diffusion coefficient in grain boundary) was also determined and it was found that it obeys the Arrhenius law P - 7.2 × 10~(-15) × exp (-46 kJ mol~(-1)/RT) m3 s~(-1).