Nanostructures and mechanical properties developed in copper by severe plastic deformations

The development of the nanostructure in commercial pure copper and the strength and ductility after severe plastic deformation (SPD) with the technology of equal channel angular pressing (ECAP) are analysed. Experimental results and analyses show that both strength and ductility can be increased simultaneously by SPD. The final grain size decreased from the initial 50 mum by SPD to 100-300 nm after 10 passes. An increase of the ductility together with an increase of strength caused by SPD is explained by a strong grain refinement and by a dynamic equilibrium of weakening and strengthening, and it is visible on the final static tensile test stress-strain charts.