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

W–Sc 2 O 3 composite powders (W, W–0.5 vol%Sc 2 O 3 , and W–2 vol%Sc 2 O 3 ) doped with highly uniform Sc 2 O 3 particles were successfully synthesized by mechanical alloying followed by hydrogen reduction with Sc 2 O 3 and WO 3 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 Sc 2 O 3 particles were uniformly distributed in the tungsten grains and grain boundaries. The W–2vol%Sc 2 O 3 composite possess the best relative density and Vickers micro-hardness up to 98.6% and 683.2 Hv, respectively. The Sc 2 O 3 particles significantly refine the grain size and increase the density of tungsten alloy. With increased Sc 2 O 3 content, the thermal conductivity decreased while tensile strength of the samples respectively increased at 700 and 800 °C.