Effect of high pressure torsion on microstructure of Cu-Sn alloys with different content of Hume Rothery phase

Abstract

Two copper alloys with 7.8 and 23at.% tin with different content of ε Hume Rothery phase were subjected to high pressure torsion (HPT) at room temperature. The initial state of both alloys before HPT was quite different. The first alloy contained the Cu matrix (α-phase) with uniformly distributed precipitates of ε-phase, while another consisted of alternating plates of the ε phase and fine-grained (α+ε) mixture. Strong grain refinement of α phase to the nanometer range and partial dissolution of ε phase in Cu-matrix were observed in the Cu–7.8at.% Sn alloy after HPT. The Cu–23at.% Sn alloy after HPT revealed neither the grain refinement nor dissolution of phases.