Quench-hardening of aluminium and aluminium-magnesium by sub-microscopic defects

Abstract
Comparison of the effect of ageing on the flow stress of water-quenched and air-cooled aluminium and aluminium-magnesium alloys has clearly demonstrated that the hardening is inversely related to the concentration of visible dislocation loops. Hardening by more highly dispersed vacancy clusters is therefore postulated and the results interpreted in terms of the bowing of moving dislocations pinned by the lattice defects. Results are compared with the several variations proposed on the Orowan model for such a process.