Microstructural refinement and intermetallic formation in an Al–5Cu alloy consolidated by high-pressure torsion.

Abstract

Bulk Al–5Cu (wt.%) was successfully fabricated from commercial Al and Cu powders at room temperature using high-pressure torsion up to 50 turns. The microstructure near the edge of the disc was heterogeneous with an Al-rich solid solution matrix having an average grain size of ~110±20 nm and regions with lamellae bands in a supersaturated solid solution containing nanosized grains of ~25±5 nm. A partial dissolution of Cu into the Al matrix occurred concurrently with the formation of Al2Cu and Al4Cu9 intermetallic phases. A high microhardness of 200-230 Hv was reached at the edge of the disc. This study demonstrates the ability to engineer a novel Al-Cu system by processing via severe plastic deformation.