Refractory high entropy alloys have shown potential to be developed as structural materials for elevated temperature applications. In the present research, the multielement alloy Fe2TiVZrW0.5 was produced by high-energy ball milling of elemental powders in the air to promote the formation of reinforcing oxide and nitride particles followed by spark plasma sintering consolidation. The sintering temperature was optimized to achieve a full-density material that was characterized from the microstructural and mechanical points of view. Hardness and KIC were measured in the as-sintered condition as well as after thermal treatment at 1100 °C. TEM observations showed the presence of a fine distribution of ZrO₂ and Ti(V)-N in the microstructure mainly constituted by the bcc Fe-V and Fe-V-W phases. The fine distribution of ceramic particles in a metallic multielement matrix is responsible for the consistent hardness and thermal stability of this alloy.

In the present work, three different AlCoxCrFeNi (x = 1, 0.75, 0.5) alloys were produced through the mechanical milling of powders and spark plasma sintering. These alloys were characterized in terms of their microstructural, mechanical, and oxidation behaviors. Mechanical milling and spark plasma sintering were chosen to achieve a fine and homogeneous microstructure. Pore-free samples were produced by properly setting the sintering parameters. The unavoidable uptake of oxygen from the powders when exposed to air after milling was advantageously used as a source of oxides, which acted as reinforcing particles in the alloy. Oxidation behavior, studied through TGA tests, showed that decreasing the Co content promotes better oxidation protection due to the formation of a dense, compact Al₂O₃ layer. The alloy containing the lowest amount of Co is considered a good candidate for high-temperature structural applications.