Early-stage phase separation in liquid-quenched Al-7 at % Zn

The kinetics of GP zone formation in liquid-quenched Al-7 at % Zn was studied with small-angle X-ray scattering. It is found that liquid quenching yields a solid solution in the as-quenched condition which is significantly less clustered than for solid quenching. In addition, the ageing kinetics of the liquid-quenched specimens was observed to be significantly slower than that for solid-quenched specimens. The results indicate that slow ageing in liquid-quenched alloys results from the absence of a high concentration of quenched-in mobile vacancies. It is thus suggested that liquid quenching effectively enables studies of the earliest stages of phase separation in precipitation-hardenable alloys.