Unveiling the internal oxidation mechanism in Cantor alloys: Role of Laves phase and Ta variations

The complex relationship between temperature, tantalum (Ta) content, and oxidation behavior in Cantor alloys reveals a novel internal oxidation mechanism. Oxidation proceeds via a distinct two-stage process, where temperature and Ta content play critical roles in determining the evolution of oxide layers. The in-situ oxidation of the Laves phase triggers elemental redistribution, resulting in the formation of CrTaO₄ particles along grain boundaries and a continuous CrTaO₄ layer at the oxide/matrix interface, dramatically improving oxidation resistance. Unlike conventional alloys, where Laves phase precipitation restricts oxygen and metal ion diffusion, this mechanism drives advanced protective oxide development, advancing alloy engineering.