Microstructural evolution and mechanical properties of a two-phase Cu–Ag alloy processed by high-pressure torsion to ultrahigh strains

Disks of a coarse-grained Cu–28 wt.% Ag alloy were processed by high-pressure torsion up to 20 revolutions to reveal the microstructural evolution and mechanical properties. The eutectic shows a faster evolution process than the Cu matrix. A banded structure forms in the Cu matrix, and both the eutectic spacing and the band width decrease with increasing shear strain. After 20 revolutions, the substructure may even diminish in the Cu matrix. The microhardness increases with increasing revolutions, and a saturation microhardness is ultimately achieved. After 20 revolutions, the tensile strength was improved to ∼1420 MPa, and the failure mode of the sample was transferred from necking to full shearing without plasticity.