Two-step ageing and final size of G.P. zones in Al-Zn 10% alloy

Abstract
The effect of pre-ageing at 0°C on the subsequent ageing at 40°C (two-step ageing) in Al-Zn 10% alloy is investigated by X-ray small-angle scattering and resistivity measurements. The size of G.P. zones at the end of the two-step ageing is found to increase on increasing the time of pre-ageing, a result which is related to the influence of temperature on zone size in single-stage ageing.