Deformation Behavior and Microstructural Evolution of Cu-Ag Alloys Processed by High-Pressure Torsion

In this study, different Cu-Ag alloys (Cu-10/25/50/75/90 wt% Ag) are produced by powder consolidation and subsequent high-pressure torsion processing. The microstructural evolution of the material state is investigated by SEM and TEM. Additionally, mechanical properties are characterized by Vickers microhardness measurements. The deformation mechanism changes from homogenous code-formation in the very beginning of the process to shear banding. When the hardness reaches a saturation level, all compositions show grain sizes below 100 nm with a very high defect density and hardness compared to pure ultrafine-grained Cu or Ag. Single-phase solid solutions are reached at both high and low Ag content, in the medium composition range a mixture of single-and two-phase regions is observed.