Microstructure and Properties of Cu-0.4 wt.% Al₂O₃ Composites Fabricated by Hot Extrusion and Cold Drawing

In the present study, Cu-0.4 wt.% Al₂O₃ composites were successfully prepared by internal oxidation and hot extrusion followed by cold drawing. Microstructure, texture, mechanical properties and electrical conductivity of the Cu-0.4 wt.% Al₂O₃ composites were systematically studied. Our results show that the cold drawn S2 sample contains a much finer grain (about 1 μm) than the extruded S1 sample (about 3 μm). The S1 and S2 samples have a typical double fiber texture, with <100> and <111> parallel to extrusion direction (ED) or drawing direction (DD). The ultimate tensile strength, tensile yield strength and electrical conductivity of S1 sample are 460 MPa, 375 MPa and 90% IACS, respectively. After cold drawing, the S2 sample possesses a higher ultimate tensile strength (560 MPa) and tensile yield strength (520 MPa) than S1 sample, but a slightly lower electrical conductivity (87.5% IACS) than S1 sample. After annealing at 900 °C, the S1 and S2 samples also have a high microhardness of about 125 HV, which indicates that the Cu-0.4 wt.% Al₂O₃ composites have an excellent thermal stability.