Cr₂AlC-induced improvements in oxidation resistance and surface stability of VCoNi alloys at intermediate temperatures

This work investigates the influence of Cr₂AlC additions (1 and 4 wt.%) on the microstructure, oxidation behavior, and mechanical performance of VCoNi alloys. All alloys maintained a single-phase face center-cubic ( fcc ) structure after sintering, but Cr₂AlC-containing samples showed the formation of (Cr,V)₂AlC-type phases. High-temperature oxidation tests revealed significantly reduced oxidation rates in the 4% Cr₂AlC alloy at 800 °C. While all alloys developed the same sequence of oxide layers, Cr₂AlC additions led to a more compact morphology, reduced surface roughness, and increased hydrophobicity over time. Surface stabilization was especially pronounced in the 4% Cr₂AlC alloy, which exhibited the highest contact angle and lowest surface energy. Mechanical tests conducted prior to oxidation showed a moderate reduction in bending strength and elastic modulus due to Cr₂AlC additions, retaining values above 890 MPa. The results indicate that Cr₂AlC effectively enhances oxidation resistance while preserving aceptable mechanical integrity, offering a tunable route for enhancing high-temperature performance in fcc multi-principal element alloys.