On the effect of addition elements on the primary recrystallization process of aluminium (1st Report)

Abstract

On the primary recrystallization process of the binary alloys which 9 elements, such as Mn, Cr, Si, Ti, Zn, Mg, Cu, Fe and Ni are respectively added to superpurity aluminium up to 2%, the growth rate of nuclei—G, the rate of nucileation—N, the rate of recrystallization—R and ther activiation energies—Q_R, Q_G, Q_N and the relationship between the as-recrystallized grain size—Df and N/G have been measured at the working degree of 5% and 10% respectively. From the results, the influences of temperature, deformation and added elements to properties of these alloys have been studied. The experimental results will be described in this paper and the theoretical considerations will be in the following paper.
The experimental results are summarized as follows:
(1) Under the working strain of ε, the following equation has been proposed on G of super-purity aluminium binary alloys.
G_ε=(1-m)D_1εΔF₁/λRT+mD_2ε(ΔF₁-U)/λRT…eq. (2)
This equation shows that the smaller the diffusion coefficient D₂ of added elements in solvent aluminium is, the greater the difference § of atomic size of both metals or the interaction energy U for foundary dislocation, and the more the amount m of added elements is, the more rapid decrease in G (Fig. 7)
(2) The effect of added elements on R shows the same tendency as that on N (Fig. 11, 16)
(3) The relationship between the as-recrystallized grain size D_f and N/G is shown by the following equation: Df=k(N/G)ⁿ…eq. (9) Greater the N/G is, smaller is the D_f (Fig. 20).
(4) In the case of up to 10% strain by elongation, while Mn, Cr and Si tend to coarsen the as-recrystallized grain size Df with the increase insamounts of their addition, other elements refine it (Fig. 21).