Preparation and properties of multiphase solid-solution strengthened high-performance W–Cu alloys through alloying with Mo, Fe and Ni

In this study, high performance W–Mo–Cu–Ni–Fe alloy samples with additions of Mo (0–6 wt%), Ni and Fe (total content: 2.5 wt% and 5 wt%) were obtained through liquid-phase sintering at lower temperature, with the raw material of ultrafine W–Mo–Cu–Ni–Fe composite powder. Ultrafine W–Mo–Cu–Ni–Fe alloy powder with strong sintering activity and uniform composition was obtained by two-stage reduction means composed of carbothermic pre-reduction and hydrogen deep deoxidation steps. Significantly, the bonding ability of W/Cu phase interface and the wettability of two phases are greatly improved due to the presences of Ni and Fe. Moreover, the addition of appropriate Mo content was advantageous to the formation of W–Mo solid solution. All alloy samples achieved higher densification degrees to guarantee that the sintered blocks possess outstanding overall performances. Especially, by adjusting Ni/Fe ratio, the highest tension strength and elongation of were achieved by W-2wt.%Mo-1.75 wt%Ni-0.75 wt%Fe-27.5 wt%Cu sintered block, which were 567 MPa and 10.37%, respectively. Moreover, owing to the presences of W–Mo and Cu–Ni–Fe solid solutions, this alloy also had the highest microhardness and bending strength of 446 HV and 1473 MPa, respectively. As increasing Mo content from 0 wt% to 6 wt%, the compression strength of sintered blocks was improved, and failure strains of all the sintered blocks are close to 100%, respectively. However, even though the Cu matrix network structure is more evenly distributed as a result of the existences of added Ni and Fe, the electronic movement ability of the sintered blocks was reduced, leading to a significant decrease in conductivity.