Investigation on the microstructure and mechanical properties of the spray-formed Cu-Cr alloys

Cu-1.2 wt.%Cr and Cu-3.2 wt.%Cr alloys were prepared by spray forming. The as-deposited alloys were subsequently warm rolled at 300 °C with a 40% reduction and then two types of thermo-mechanical treatments were adopted to enhance the mechanical properties of the Cu-Cr alloys. The microstructural features of the Cu-Cr alloys in different thermo-mechanical processing conditions were characterized using optical, scanning electron and transmission electron microscopy techniques. The results show that the spray-formed Cu-Cr alloys exhibit a better response to heat treatment compared to the conventional casting alloys. The chromium content has a great effect on the aging behaviors of the Cu-Cr alloys. Although a higher chromium content leads to a larger volume fraction of chromium precipitates generated during the solidification, it does not cause an increase in the mechanical properties. The chromium content should be lower than 1.2 wt.%.