Establishment of processing map, microstructure and high-temperature tensile properties of W-0.25 wt% Al2O3 alloys

The sintered Al2O3-reinforced tungsten alloys were fabricated via hydrothermal process and powder metallurgy method. Subsequently, the compression tests of sintered W-0.25 wt% Al2O3 alloy with Gleeble 1500D thermal simulator were conducted in the temperature range of 1300–1600 °C and strain rate range of 0.01–10 s−1. The processing map of the sintered W-0.25 wt% Al2O3 alloy was established and the swaged W-0.25 wt% Al2O3 alloy was obtained by hot working on the basis of the data analysis from the processing map. For the swaged W-0.25 wt% Al2O3 alloys annealed at various temperature, the mechanical properties are obviously reduced, and recrystallization temperature of the swaged W-0.25 wt% Al2O3 alloys is above 1600 °C, at least 200 °C higher than of the swaged pure tungsten. The Al2O3 particle is well combined with the W matrix. In addition, there is a transition layer between the Al2O3 particles and W matrix. The swaged W-0.25 wt% Al2O3 alloys possess high strength of 611 MPa with a total elongation of 45% at 800 °C. The ultimate tensile strength of the swaged W-0.25 wt% Al2O3 alloys are always higher than that of the swaged pure W alloys at different temperatures, indicating that the addition of Al2O3 particles can effectively pin dislocations and grain boundaries, thus improving the high-temperature strength of alloys. © 2020 Elsevier B.V.