Structure and microhardness of Al-Pt composites produced through consolidation of the elemental chips by high pressure torsion

The production of Al-based composites with high functional properties is an urgent scientific problem, the results of which may be of interest for practical application. That is why, there is an increasing interest in using the high pressure torsion (HPT) method to consolidate mixtures of aluminum with different metal powders and obtain new materials with promising properties. In the work, we obtained a novel metal-matrix composite, in which a soft Al-matrix is strengthened by hard and inert Pt-particles. The evolution of the phase composition and microhardness of the discs, which were produced by HPT of mixture Al+Pt chips, are investigated. Severe plastic deformation and large shear strain implemented under HPT lead to amorphization and solid solutions based on both Al and Pt. According to our estimation, near 5 at.% Al dissolved in Pt after the room-temperature HPT. Despite the fact that Pt is practically insoluble in Al, the XRD results of the Al-Pt disc suggest the formation of a non-equilibrium solid solution containing 2.1 at.% Pt in the Al matrix. The aluminum and platinum disks were also obtained and investigated. It was revealed, that the microhardness of the Al-Pt composite disc is between the microhardness values of Al- and Pt-discs.