The effect of strain path and temperature on the microstructure developed in copper processed by ECAE

Abstract

The microstructure of copper developed by equal channel angular extrusion (ECAE) to a strain ∼8 was investigated using different strain path and temperature. Two different strain paths were obtained by rotating the billets through 90° (route B C) or 180° (route C) between each pass. In general, the microstructure should be characterized as a cold-worked structure with varied degree of recrystallization depending on the processing route and temperature. At room temperature, both routes produced similar microstructure except the formation of recrystallized grains by route B C. By the use of route B C, the volume fraction and size of recrystallized grains were found to increase with increasing deformation temperature, while the size of recrystallized grains showed considerable increase above 150 °C. Comparing with aluminum deformed by ECAE at similar homologous temperature (∼0.32 T m), the most distinct difference in the microstructure development is the presence of dynamic recrystallization in copper.