Effect of Mo content on the thermal compression properties and microstructure evolution of WMo-Al2O3 alloys

Abstract

A WMo–Al₂O₃ composite powder was prepared using a wet chemical method, followed by cold isostatic pressing and two-stage sintering (medium-frequency induction sintering and hot isostatic pressing). Subsequently, a WMo–Al₂O₃ alloy was fabricated. The thermal compression properties of the WMo–Al₂O₃ alloy were evaluated with different Mo contents (10, 20, 30, 40, and 50 at.%) at high temperatures (1300 °C–1600 °C). The findings revealed that introducing Mo through doping markedly refines the grain size, as determined by analyzing the thermal compression behavior and microstructural evolution of WMo–Al₂O₃ alloys with varying Mo contents. The grain size of the W–Al₂O₃ alloy was ∼30.12 μm, while that of a W–30Mo–Al₂O₃ alloy after two-stage sintering was 25.61 μm, which is ∼4.51 μm smaller, corresponding to a grain size reduction of 14.97 %. Under the compression test condition of 1300 °C and 0.005 s⁻¹, the compressive strength of WMo–Al₂O₃ alloys with different Mo contents was higher than that of W–Al₂O₃, indicating that Mo incorporation enhances the high-temperature mechanical performance of WMo–Al₂O₃ alloys. Moreover, the geometric necessary dislocation density of the W–30Mo–Al₂O₃ alloy was the highest among the tested samples, corresponding to the highest compressive strength.