Fabrication of high-strength metallic materials with heterostructure prepared via flow control extrusion

Abstract

Abstract This paper proposes a novel approach called flow control extrusion (FCE) to obtain functional properties in metallic materials. The microstructure of pure copper subject to this technology combine ultrafine-grained structure in the surface layer, heterogeneous lamella structure inward, and gradually transits to bimodal grain structure in the center. Compared with the sample subject to conventional extrusion (CE), FCE extruded pure copper have higher yield strength (443\xa0MPa) and work hardening rate. The high strength mainly depends on the significant refinement of microstructure. The high work hardening rate attributes to the back-stress-induced strengthening and dislocation hardening developed from the heterostructure of grain size and crystal orientation.