Research on preparation process for the in situ nanosized Zr(Y)O2 particles dispersion-strengthened tungsten alloy through synthesizing doped hexagonal (NH4)0.33•WO3

In this article, the in situ nanosized Zr(Y)O-2 particles uniformly distributed in the tungsten alloy was successfully prepared through synthesizing doped alpha-HATB powder and spark plasma sintering process. The processing route involves a molecular-level liquid-liquid doping technique that causes a large number of nanosized particles within tungsten grains. The synthesis mechanism of alpha-HATB and phase evolution were detailedly investigated. Over 75% of W-Zr(Y)O-2 powders particles are less than 3 mu m. The determined S-w values (5.7), coefficient of uniformity C-u (2.3) of the W-0.5% Zr(Y)O-2 doped tungsten are 5.7 and 2.3, respectively, both indicating the narrower size distribution. The average size of Zr(Y)O-2 particles in prepared W alloy are about 250 nm under SEM observation. Through milling of these powders, the particles in W-0.5%Zr(Y)O-2 alloy and 92.25W-4.9Ni-2.1Fe-0.75ZrO(2) can further decrease to less than 100 nm in size, which are 8-10 times smaller than those in the state-of-the-art review. (C) 2020 Elsevier B.V. All rights reserved.