Formation of ultrafine-grained (UFG) structure and mechanical properties by severe plastic deformation (SPD)

Abstract

Commercial pure cooper (99,9% Cu) was deformed by equal channel angular pressing (ECAP) using up to 10 passes, route C. The evolution of microstructure and fracture character were observed by OM, SEM and TEM. The mean grain size decreased with increasing deformation, after 10 passes to 100 – 300 nm. TEM analysis suggested the possible nanostructure formation mechanism by the formation of cellular structure in grains, forming of subgrains and then forming of high angle nanograins with random orientation. Fractures of ECAP Cu material after 10 passes had transcrystalline ductile character with dimple morphology