Effect of Sc2O3 particles on the microstructure and properties of tungsten alloy prepared by spark plasma sintering

W-Sc2O3 composite powders (W, W-0.5 vol%Sc2O3, and W-2 vol%Sc2O3) doped with highly uniform Sc2O3 particles were successfully synthesized by mechanical alloying followed by hydrogen reduction with Sc2O3 and WO3 powders. The reduced powders were then consolidated by spark plasma sintering at 1700 °C to suppress grain growth during sintering. Field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and high-resolution transmission electron microscopy analyses, as well as tensile tests and thermal conductivity measurements, were used to characterize the samples. The results showed that the Sc2O3 particles were uniformly distributed in the tungsten grains and grain boundaries. The W-2vol%Sc2O3 composite possess the best relative density and Vickers micro-hardness up to 98.6% and 683.2 Hv, respectively. The Sc2O3 particles significantly refine the grain size and increase the density of tungsten alloy. With increased Sc2O3 content, the thermal conductivity decreased while tensile strength of the samples respectively increased at 700 and 800 °C.