Diffusion of 65 Zn in Mg and in Mg– x Al solid solutions

Heterodiffusion of 65 Zn in Mg, Mg– x Al ( x = 1.77, 3.9 and 9 wt% Al) and 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 the Zn bulk diffusion coefficient D is described by the relation D = exp (0.1 c Al – 9.16) exp (–125.8 kJ mol –1 / RT ) m 2 s –1 ( c Al – concentration of Al in wt%). The Zn grain boundary diffusivity P = sδD b ( s – segregation factor, δ – grain boundary width and D b – diffusion coefficient in the grain boundary) was also determined and obeyed the Arrhenius law P = 7.2 × 10 –15 exp (–46 kJ mol –1 / RT ) m 3 s –1 . (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)