Compressive properties and deformation behaviors of sintered W-m-ZrO2 alloy under different temperature

Abstract

The compressive properties of sintered tungsten alloys with different m-ZrO2 weight percentage (0, 0.5, 1.0%) were tested at room temperature and high temperature, and the hot deformation behaviors of the three metals were investigated under different temperature (1300–1600 °C) and strain rate (0.005–1 s−1). The room temperature strengthening model of zirconia particle reinforced tungsten alloy was established, and the hot deformation activation energy and constitutive equation of the three metals were calculated. Characterized by field emission scanning electron microscopy (FE-SEM) and the electron back scattering diffraction (EBSD) technique, the results show that zirconia doping can significantly refine the tungsten grain size, improve sintering densities, and uniformly disperse in the boundaries and inside of tungsten grain. The room temperature compression results show that the ultimate compressive strength and strain-to-failure of W-1.0 m-ZrO2 increase by 51.94% and 96.69%, respectively compared with pure tungsten. The main contribution to the room temperature strength of tungsten alloys is the fine grain strengthening caused by zirconia doping, about 60% for W-1.0 m-ZrO2，while the strengthening of the secondary phase particles accounts only for about 5%. High-temperature compression results show that zirconia doping increases the dislocation density of the alloy and significantly improve the ultimate compressive strength under high-temperature compression, but the influence of zirconia content on the strength will be weakened at high temperature. The doping of zirconia reduces the hot deformation activation of tungsten alloys and improves the hot processing behavior of tungsten alloy.