Effect of rhenium addition on the microstructure, high temperature mechanical and tribological properties of WMo alloy

Abstract

To meet the growing demand for materials capable of withstanding extreme high-temperature environments encountered in hypersonic aircraft and the nuclear industry, this study prepared a series of ternary refractory alloys (WMo)_1-x(Re)_x with varying Re mass fractions (x = 0, 5, 10, and 20 wt%) via powder metallurgy techniques. The influences of Re addition on the alloys' microstructure, phase composition, high-temperature mechanical properties, as well as friction and wear behavior over a broad temperature range were systematically investigated. Results indicate that Re addition significantly refined grain structure and promoted uniform distribution of Mo, primarily due to the formation of WMoRe solid-solution-based multiphase structures brought about by solid-solution strengthening and inhibition of grain coarsening. Mechanical tests demonstrated that both the hardness and yield strength of alloys exhibited concentration-dependent enhancements with increased Re content. Furthermore, the tribological properties showed a ternary mapping relationship involving temperature, composition, and wear mechanisms. Specifically, the incorporation of Re effectively suppressed oxidation layer formation below 600 °C, while at 800 °C, the excessive formation of oxides degraded the tribological performance of alloys.