Preparation and properties of excellent performance W–Cu alloy with a variety of strengthening mechanisms

Abstract

In this paper, using the ultrafine W-27.5 wt%Cu-2wt.%Mo-1.75 wt%Ni-0.75 wt%Fe-(0–1)wt.%CeO2 alloy powders as raw materials, W–Cu–Mo–Ni–Fe–CeO2 alloys with excellent performances were prepared by low temperature sintering. Two-step reduction method consisting of carbothermic pre-reduction and hydrogen deep deoxidation was used to produce ultrafine W–Cu–Mo–Ni–Fe–CeO2 alloy powders with uniform distributed composition. All sintered blocks obtained relatively high densification degree (97.1 %∼99.2 %) to ensure the excellent comprehensive properties. Moreover, the existences of γ-(Cu, Ni, Fe) and W–Mo solid solutions ensured the alloy possessed a high mechanical strength. More importantly, the introduction of CeO2 inhibited the growth of W–Mo grains. With increasing CeO2 content from 0 wt% to 1 wt%, the W–Mo grain size decreased from 1.76 μm to 1.44 μm. Especially, alloy sample with the highest tensile and compressive strengths was obtained by adding 0.5 wt% CeO2, which were 602 MPa and 3187 MPa, respectively. Furthermore, owing to finer W–Mo grain size, this sample also possessed the maximum micro-hardness and bending strength of 482 H V and 1685 MPa, respectively. Nevertheless, the existences of Ni, Fe and CeO2 also destroyed the electrical conductivities of the samples to some extent. Specifically, with increasing CeO2 content from 0 wt% to 1 wt%, the electrical conductivity of the sample decreases from 32.56 %IACS to 30.16 %IACS.