Effect of backpressure on structure and properties of AA5083 alloy processed by ECAP

An ultrafine-grained microstructure was obtained in bulk billets of 20mm×20mm×80mm from commercial AA5083 alloy by equal channel angular pressing (ECAP) at the ambient temperature with a different number of passes and the backpressure level. Backpressure enhances workability of alloys processed by ECAP. Strength and microhardness of AA5083 alloy were significantly enhanced. The room strength and microhardness (UTS=427MPa, 165HV) of initially course-grained alloy, subjected to three passes of ECAP with backpressure 200MPa, are much higher than its standard values after convention processing by hot pressing or cold rolling. © 2004 Elsevier B.V. All rights reserved.