Superplasticity in AI–17 wt.-%Cu Alloy

Abstract

Hot-rolled Al–17%Cu alloy deforms superplastically at elevated temperatures with large values of strain-rate sensitivity(> 0·30) and large, neck-free elongations (> 200%). Two mechanisms appear to be involved in the deformation process. At lower stresses and strain rates the activation energy of the deformation process is similar to that for grain-boundary diffusion while at higher stresses and strain rates the activation energy corresponds to that for volume diffusion. The room-temperature properties of hot-rolled Al–17%Cu alloy are comparable to those for conventional Al alloys but superplastic deformation at elevated temperature causes a deterioration of room temperature properties because of agglomeration and sintering of the Al₂Cu intermetallic phase.