Effects of specimen surfaces, grain boundaries and sceondary defects on aging and reversion of Al-2mass%Cu alloy.

Abstract

Variation of hardness with position in the grain was measured during aging and reversion of Al-2 mass%Cu alloy.Age-hardening was suppressed in the surface layer relative to the interior of the specimen aged at 273K after quenching from 823K. Rate of reversion was faster in the surface layer than in the interior when the age-hardened specimen was annealed below 403K where few secondary defects should decay. When the specimen aged after quenching from high temperature was annealed at 403K, the surface layer and the interior softened nearly at the same rate. Those softenings appeared also in the regions near grain boundary.