Effect of Surface and Grain Boundary on the Reversion of Al-Zn Alloys

摘要

Age-hardening of an Al-Zn alloy after quenching develops inhomogeneously due to the effect of surface as a vacancy sink and grain boundary as an easy path. In this study, reversion of the age-hardened Al-Zn alloys, in which ellipsoidal GP zones were formed, was investigated by Vickers micro-hardness test. Ellipsoidal GP zones were reverted more quickly near the surface and grain boundary than in the interior, e.g. similar to spherical GP zones in an Al-10% alloy. It is considered that the surface and grain boundary play a role as an effective source for vacancies, in addition to the interior source such as dislocations, as in the case of the reversion of spherical GP zones.