Effects of Heat Treatment on Mechanical Properties of W-Cu-Zn Alloy with Low W-W Contiguity

W-Cu-Zn alloy with Cu-Zn matrix and low W-W contiguity was prepared by electroless copper plating combined with SPS solid-phase sintering. The influence of heat treatment on the microstructure and mechanical properties of the alloy was investigated. Microstructure analysis reveals that tungsten particles distribute in the Cu-Zn matrix phase homogeneously. The Cu-Zn matrix phase is α-phase solid solution. The distribution of tungsten particles and Cu-Zn matrix phase does not change after the normalizing heat treatment. However, the mechanical properties of W-Cu-Zn alloy are evidently improved after annealing at 870℃ followed by furnace cooling. Under quasi-static compression, the strength of W-Cu-Zn alloy increases from 650 MPa to 750 MPa, and the critical failure strain increases from 0.18 to 0.26. While under dynamic compression, the strength of W-Cu-Zn alloy increases from 710 MPa to 900 MPa, and the critical failure strain increases from 0.24 to 0.4. The hardness (HV) increases from 1438 MPa to 1723 MPa. Mechanism analysis shows that there are two factors contributing to improvement of the mechanical properties of W-Cu-Zn alloy. Firstly, the distribution of element Zn is inhomogeneous within the original W-Cu-Zn alloy. The specimen processed by annealing at 870℃ followed by furnace cooling exhibits more homogeneous distribution of Zn within the matrix. Secondly, a large number of fine Cu₃Zn precipitates are formed uniformly in the Cu-Zn matrix phase of W-Cu-Zn alloy after annealing at 870℃ followed by furnace cooling, which plays a role of dispersion strengthening.