Microstructure Evolution and Strengthening Mechanism of Regenerated Brass Alloy under Fe-Mn Control during Cold Drawing

Fe from raw materials and processing are inevitably introduced in the direct regeneration process of brass alloys from scrap copper, which may significantly affect the cold working performance of regenerated brass. Developing regenerated brass alloys that can be used for cold drawing under large deformation amounts remains a challenge. In this paper, the regenerated brass alloy wire was prepared by the method of Fe-Mn in-situ control casting and hot extrusion. The plasticity of regenerated brass was significantly improved during cold drawing after Fe-Mn microalloying control. The direct single pass ultimate cold working rate can reach 42% and the yield strength, tensile strength, total elongation, and hardness were 635 MPa, 649 MPa, 3.5%, and 181.2HV, respectively. Cold drawing wires showed good torsional resistance. The evolution of microstructure and properties of regenerated brass during cold drawing was studied, and the strengthening mechanism was determined. Work hardening induced by dislocation strengthening is the dominant strengthening mechanism. In the cold drawing process, the α phase of the FCC structure and the β phase of the BCC structure form a good coordination between soft and hard domains. The accumulation of dislocation introduced in the cold drawing process, the synergistic effect of the sliding mechanism, and the nanotwin deformation mechanism ensure the ideal cold drawing performance of the regenerated brass.