Effect of copper content on the dynamic compressive properties of fine-grained tungsten copper alloys

Experiments were conducted to evaluate the effect of Cu contents on the microstructures and dynamic compressive properties of three kinds of fine-grained tungsten copper (W-Cu) alloys with Cu contents in the range of 20-40 wt% prepared by isostatic cold pressing and infiltration. With the Cu content decreases from 40% to 20%, W grains grow slightly together with the W-W contiguity increasing and the homogeneity of microstructure improving. The dynamic yield strengths show an obvious increased tendency from 320 MPa in 60W-40Cu alloy to 1100 MPa in 80W-20Cu alloy. The yield strengths of the alloys show obvious strain rate strengthening effect. The three fine-grained W-Cu alloys exhibit good plasticity under compression with the dynamic critical failure strains of 0.6-0.85. The fracture mechanism is dependent on Cu content. The main failure modes are tearing of Cu phase, separation of W-W boundaries along with tearing of Cu phase, and failure of W shearing bands in 60W-40Cu, 70W-30Cu and 80W-20Cu alloys, respectively.