Abstract
Disks of AA6061 reinforced with 0 and 15%SiC were processed via a combination of hot compaction (HC) of the mixed powders followed by high pressure torsion (HPT). HPT was conducted using two deformation modes; continuous rotation in a forward direction (monotonie (m-HPT)) and reverse rotation (cyclic (c-HPT)) over a number of revolutions under 1-GPa pressure at room temperature. Hardness profiles of sections cut parallel and perpendicular to load direction revealed that one revolution produced nonuniform distribution of strain-hardening, where highest hardness was displayed at the disk edges and lowest towards the centers. Increasing number of revolutions via m-HPT enhanced the hardness uniformity across the discs. Although, c-HPT produced equiaxed structure with high hardness, it was unable to eliminate the nonuniform distribution of properties across the discs even after 4 revolutions. HPT processing increased the Hv of HC disks by 280 and 200% for AA6061 with and without SiC reinforcement, respectively.