Effects of heat treatment processes on the microstructures and properties of powder metallurgy produced Cu-Ni-Si-Cr alloy

The microstructure analysis suggested that the hardness or tensile strength increased after an aging heat treatment due to the large number of nanometer-sized precipitates of β-Ni3Si and δ-Ni2Si phases that were formed. The optimal heat treated P/M copper alloy (8-h solution heat treatment at 970 °C followed by 6-h aging at 450 °C) had an extremely good combination of an average sub-grain size (<30 μm), an average tensile strength (up to 820 MPa) and an average thermal conductivity (110 W/mK), which offers possibilities for application in mold tooling.