Heterodiffusion of 65Zn in Mg, Mg-xAl (x = 1.77, 3.9 and 9wt%Al) and the commercial alloy was studied at 498 to 848K (tables 6 and 7) by using serial sectioning and residual activity methods. The concentration and temperature dependence of the Zn bulk diffusion coefficient was described by the relationship:

D(m2/s) = exp[0.1cAl(wt%)-9.16]exp[-125.8(kJ/mol)/RT]

The Zn grain boundary diffusivity P = sδDb (table 8) obeyed the relationship:

P(m3/s) = 7.2 x 10-15exp[-46(kJ/mol)/RT]

Diffusion of 65Zn in Mg and in Mg-xAl Solid Solutions. J.Cermák, I.Stloukal: Physica Status Solidi A, 2006, 203[10], 2386-92

 

Table 7

Diffusion of 65Zn in AZ91 (Mg-9Al-1wt%Zn)

 

Temperature (K)

Condition, Method

D (m2/s)

723

as-received, serial sectioning

2.61 x 10-13

723

as-received, residual activity

3.25 x 10-13

723

annealed (688K, 30h), serial sectioning

2.19 x 10-13

723

annealed (688K, 30h), residual activity

2.30 x 10-13

698

as-received, serial sectioning

8.71 x 10-14

698

as-received, residual activity

6.82 x 10-14

698

annealed (688K, 30h), serial sectioning

9.45 x 10-14

698

annealed (688K, 30h), residual activity

8.71 x 10-14

673

as-received, serial sectioning

5.39 x 10-14

673

annealed (688K, 30h), serial sectioning

4.34 x 10-14

673

annealed (688K, 30h), residual activity

4.09 x 10-14

648

as-received, serial sectioning

2.05 x 10-14

648

as-received, residual activity

1.93 x 10-14

648

annealed (688K, 30h), serial sectioning

1.76 x 10-14

648

annealed (688K, 30h), residual activity

1.80 x 10-14