Extremely uniform nanosized oxide particles dispersion strengthened tungsten alloy with high tensile and compressive strengths fabricated involving liquid-liquid method

Abstract

In this study, tungsten heavy alloys reinforced with highly uniform and dispersed nanosized Zr(Y)O2 particles were investigated. These alloys exhibited a high compressive strength and enhanced plasticity. To fabricate these alloys, we used a novel process involving molecular level liquid-liquid doping combined with hot isostatic pressing. The Zr(Y)O2 particles thus produced were smaller than 200 nm in size and bonded well with tungsten grains. The size of Zr(Y)O2 particles and tungsten grains are much smaller than those of the state-of-the-art review and the details of the grain refinement mechanisms were discussed. The effect of Zr(Y)O2 particles and strain rate on the compressive properties of the alloys was investigated in detail and the corresponding compressive deformation mechanisms were elucidated. The highest ultimate tensile and compressive strengths of the fabricated alloys at room temperature (27 °C) were 906 and 1445 MPa, respectively, which are higher than most of reported values in the literature. The ultimate tensile strength and fracture strain of WHAs decrease with the mass fraction of Zr(Y)O2 (from 0% to 0.75%). The alloys exhibit the brittle material behaviour in tension, compared to the pure tungsten with ductile material behaviour. The tensile fracture surface consists of W - W cleavage patterns and ductile failure of the matrix. The results obtained in this research will act as basic guidelines for the fabrication of ODS-W alloys by liquid-liquid doping process.