The study on low temperature sintering of a W–Ni–Cu–Sn heavy alloy

In this work, we explore the possibility of reducing the sintering temperature by designing a new tungsten heavy alloy. A new W–6.3Ni–2.7Cu–1Sn heavy alloy was fabricated by high–energy ball milling–assisted vacuum sintering. According to DSC analysis, the liquidus temperature of the alloy appears at a very low temperature, 1145 °C, and results in the densification during sintering of milled W–6.3Ni–2.7Cu–1Sn powders. 98.5% relative density was obtained with an average W grain size of 7 μm for the powder compact sintered at 1175 °C. The XRD reveal that, the phase composition of the sintered alloy surfaces are mainly composed of W phase and γ–(Ni, Cu, W, Sn) phase. In addition, the effects of sintering temperature on the microstructural characteristics and mechanical properties of the alloys were studied. The hardness and tensile strength of the alloys first increase to a maximum and then decrease as a function of sintering temperature. The highest hardness (479.5 HV) and tensile strength (752.7 MPa) were obtained at 1125 °C and 1175 °C, respectively. The mechanical properties of W–6.3Ni–2.7Cu–1Sn alloys are comparable to the conventional W–Ni–Cu alloys, despite the fact that the sintering temperature is 250 °C–300 °C lower.