抄録
Al-2.0 wt%Zn and Al-4.0 wt%Zn alloys were studied by measurements of electrical resistivity and intensity of X-ray small-angle scattering. The results obtained are: (1) There are two stages in the isochronal annealing curves when the alloys are aged at low temperature after quenching from 400°C. The amount of the change in resistivity in the second stage increases as the aging time increases, while that in the first stage decreases. (2) The second-stage reversion starts at least 10°C higher than the finishing temperature of the first stage. (3) The X-ray S.A.S. intensity from the zones reverted at the first stage can not be represented by Porod’s approximation, while that at the second stage can be approximated. (4) G.P.zones formed by the nucleation-and-growth mechanism were recognized when Al-2.0 wt%Zn alloy was aged at 0°C and Al-4.0 wt%Zn alloy at 40°C. These zones are reverted nearly in the same temperature range as the range of reversion of G.P.zones formed in the low-temperature aging from which the X-ray intensity curves can be represented by Porod’s approximation.
