Effects of stacking fault energy on the deformation mechanisms and mechanical properties of Cu and Cu alloys processed by rolling at different temperatures

Abstract

The effects of stacking fault energy (SFE) on the deformation mechanisms and mechanical properties of Cu, Cu-2.5 at.% Al-2.5 at.% Zn, and Cu-12.1 at.% Al-4.1 at.% Zn alloys processed by different rolling temperatures have been systematically investigated. Tensile tests at room temperature indicate that, as SFE decreased, strength and ductility increased, and at constant SFE the samples deformed via rolling at liquid nitrogen temperature (77 K) exhibit higher strength and better ductility than those deformed via rolling at room temperature (293 K). With lowering SFE, the crystallite size decreases while the microstrain, dislocations and twin densities increase. With decreasing temperature, there is a transition of deformation mechanism from that dominate by dislocation activities to that dominate by deformation twinning. The results indicate that decreasing SFE is an optimum method for improving the ductility of Cu and Cu alloys without loss of strength, and that temperature plays a key role in the rolling process.