Microstructural And Mechanical Characterization Of A Spark Plasma Sintered Al-Containing Refractory High-Entropy Alloy

Over the past decade, refractory high-entropy alloys (RHEAs) have been intensively studied due to their excellent high-temperature performances. Significant effort has been dedicated to reducing their density, aiming to make them competitive with Ni-based superalloys. However, RHEAs are typically produced through casting methods, which, given the high melting temperatures of their constitutive elements, may lead to inhomogeneous and coarse microstructures, thereby compromising their mechanical properties. Given this context, powder metallurgy would be a preferable route for manufacturing high-performing RHEA components. In this study, spark plasma sintering was employed to produce the biocompatible MoNbTaTiZr RHEA, later modified with the addition of aluminum to reduce its density. The microstructure and the mechanical properties of both alloys were investigated. Eventually, a component with a gradient of aluminum was also manufactured by a diffusion couple, allowing a more in-depth in...