Microstructure and activation volume of a Cu-6 wt %Zn brass processed by equal channel angular pressing

The generation of a high density of twins few tens nanometers in size can enhance both strength and ductility. The present work aims to produce highly twinned microstructure in Cu-6 wt % Zn alloy of a moderate stacking fault energy (SFE) by equal channel angular pressing (ECAP) using a die with angles phi = 110 degrees and psi = 0. X ray diffraction (XRD) shows that a high density of defects is stored up to 2 passes then a recovery takes place. EBSD imaging reveals a high density of twins and a fibrous microstructure. Grains close to 100 nm in size are formed. Strain rate sensitivity (SRS) was investigated in compression and nanoindentation (NI). Compression curves show that deformation occurs by slipping with a contribution of twins to hardening. A high contribution of shear bands was revealed during ECAP and compression tests. The activation volume V* in compression and NI is in the range 70b3 - 100b3, consistent with the emission of dislocations from grain boundaries and twin boundaries The experimental values of V* were compared to those expected from defect densities.

Automated summary

This study aims to produce a highly twinned microstructure in a Cu-6 wt % Zn alloy with a moderate stacking fault energy (SFE) using equal channel angular pressing (ECAP). The results show that a high density of defects is stored after 2 passes of ECAP, followed by recovery. EBSD imaging reveals a high density of twins and a fibrous microstructure.