Synthesis of W-Y2O3 alloys by freeze-drying and subsequent low temperature sintering: Microstructure refinement and second phase particles regulation

Abstract In this work, W-Y2O3 alloys are prepared by freeze-drying and subsequent low temperature sintering. The average size of reduced W-Y2O3 composite powders prepared by freeze-drying method is only 18.1 nm. After low temperature sintering of these composite nanopowders, the formed W-Y2O3 alloys possess a smaller grain size of 510 nm while maintaining a comparatively higher density of 97.8%. Besides a few submicron Y2O3 particles (about 100–300 nm) with a W-Y-O phase diffusion layer on their surface distribute at W grain boundaries, lots of nano Y2WO6 particles (