Effect of heat treatment on CuCrZr alloy fabricated by selective laser melting: microstructure evolution, mechanical properties and fracture mechanism

In this work, the effect of heat treatment on the microstructure and mechanical properties of CuCrZr alloy fabricated by selective laser melting (SLM) was investigated. The results demonstrated that the optimal comprehensive performance of the tensile strength (569.7 MPa) and the hardness (160 HV) was obtained by direct ageing (DA) at 470 °C for 60 min. The tensile strength of the CuCrZr alloy in the case of the solution treatment (ST) was 281.0 MPa, and the tensile strength of the CuCrZr alloy in the case of the solution + ageing treatment (SAT) reached 356.5 MPa. As the ST temperature increases, the amount of particles inside the grains dissolving into the matrix increases, the precipitation phase decreases significantly. and the precipitated phase increases slightly at the grain boundary. Zr-rich phase precipitation was observed at the grain boundaries of SA and SAT samples. The SAT and DA samples underwent recrystallisation and an increase in grain size. The grain orientation in the XZ direction of the ST samples was mainly in the direction; in the case of the SAT and the DA samples grains, the orientation became stronger.