Synergistic Effects of W and Ti on the Mechanical Performance of WxTixMoNbTaV Refractory High-Entropy Alloys

Recent research has shown a growing interest in refractory high-entropy alloys (RHEAs) due to the increasing demand for materials that exhibit exceptional mechanical strength, high ductility, excellent thermal stability and superior resistance to oxidation and corrosion. This study focuses on designing and fabricating three W_xTi_xMoNbTaV RHEAs to achieve an optimal balance between strength and ductility at room temperature. The selection strategy was based on leveraging the high strength of tungsten (W) and the excellent ductility of titanium (Ti) to develop an alloy with superior mechanical performance. Three distinct compositions (x₁ = [1, 0], x₂ = [0, 1] and x₃ = [0.5, 0.5]) were synthesised under identical conditions using mechanical alloying (MA), followed by spark plasma sintering (SPS). In our previous study, we conducted an in-depth characterisation of phase transformations during MA and the microstructural evolution after SPS. As a continuation of that research, this study explores the mechanical behaviour of these alloys, revealing exceptional properties. The results demonstrated that the combination of Ti and W is the most effective approach for developing RHEAs with an optimal strength–ductility balance, along with significantly high hardness values, achieving an impressive strength of 1300 MPa and ductility exceeding 20% at room temperature, underscoring their potential for advanced structural applications. These results locate W_xTi_xMoNbTaV alloys as strong candidates for applications in extreme refractory environments and present a promising alternative to conventional nickel-based superalloys for applications in turbines and nuclear reactor walls.