Cu–Cr–Zr alloy matrix composite prepared by powder metallurgy method

A novel Cu–Cr–Zr alloy matrix composite reinforced with Al₂O₃particles was designed and fabricated by a powder metallurgy plus hot extrusion method, in order to obtain the combined effects of aging strengthening and composite reinforcing. The CuCrZr powder was produced through water atomisation technology and used as the starting materials of the matrix. The solid solubilities of Cr and Zr elements in copper, which increased during the rapid solidification process, helped to improve the strength of the matrix after aging treatment. This was in favour of exerting the load bearing effect of the Al₂O₃reinforcements. Fabrication experiments showed that by choosing the 38 μm CuCrZr powder, cold pressed at 380 MPa and hot extruded at 400^°C, the relative densities of 7 vol.-%Al₂O₃composite reached 99·4%. The Al₂O₃particles significantly accelerated the aging process of the composites. With increasing Al₂O₃content, the Vickers hardness and ultimate tensile strength at elevated temperatures were effectively improved. The main tensile fracture mechanisms of the composites were severe plastic deformation of the matrix and the induced rupture and debonding of the Al₂O₃particles.