Preparation and properties of W-30 wt% Cu alloy with the additions of Ni and Fe elements

Abstract

In this paper, excellent performance W-Cu-Ni-Fe alloys with the addition of Ni and Fe (total content: 5 wt%) were successfully prepared by low temperature liquid-phase sintering, using the raw material of ultrafine W-Cu-Ni-Fe composite powder. Ultrafine W-Cu-Ni-Fe composite powder with high sintering activity and uniform composition distribution was prepared by a two-stage reduction method consisting of carbothermal reaction and hydrogen deep deoxidation. Additions of Ni and Fe not only improved the wettability between W and Cu two phases, but also improved the bonding strength of two-phase interface. All sintered samples had higher relatively densities to ensure that the samples have great comprehensive properties. When Ni and Fe were co-added in appropriate proportions, the highest tensile strength and elongation of W-Cu-Ni-Fe alloy samples were 497 MPa and 9.12 % for the composition: W-3.5 wt%Ni-1.5 wt%Fe-25 wt%Cu, respectively. Meanwhile, with increasing Ni content from 0 wt% to 5 wt%, the compressive strength and failure strain of alloy samples increased from 1160 MPa to 2376 MPa and from 53 % to 98 %, respectively. In addition, with the enhancement of the solid solution strengthening effects of Ni and Fe on Cu matrix, the bending strength and microhardness of the alloy samples increased to 1174 MPa and 361 HV for composition: W-3.5 wt%Ni-1.5 wt%Fe-25 wt%Cu, respectively. Although the additions of Ni and Fe made the Cu matrix network structure have a uniform distribution, it led to a decrease in the electron transfer ability of the alloy, and thus, there was a decrease in electrical conductivity.