W-Y2O3 composite nanopowders prepared by freeze-drying method and its sintering characteristics

In order to prepare high performance oxide-dispersion-strengthened tungsten based alloys, the W-Y2O3 composite powder precursors were synthesized by novel freeze-drying method. The average W grain size of prepared W-Y2O3 composite powder is 14.2 nm, and corresponding grain size distribution is extremely narrow. The low-temperature sintered W-Y2O3 alloys possess an ultrafine W grain size of about 410 nm while maintaining a comparatively high sintering density of 98.1%. The Y2O3 particles (20–50 nm) with a W-Y-O diffusion layer and Y2WO6 particles (