Outstanding 1200 °C Oxidation Resistance in a Novel Multi‐Principal Element Alloy via Lattice Distortion‐Induced Diffusion Suppression

ABSTRACT The ongoing demand for high‐thrust turbine engines necessitates the advance of next‐generation structural materials capable of withstanding higher temperatures. Commercial MCrAlY alloy, used as bond coats crucial for thermal barrier coating (TBC) systems, face a fundamental temperature ceiling of ∼1100 °C due to accelerated oxidation and spallation. Here, we design a novel Y and Hf co‐doped NiCoCrAl‐type multi‐principal element alloy (MPEA) that achieves exceptional 1200 °C oxidation resistance primarily through lattice distortion‐induced diffusion suppression. Compared with typical NiCoCrAlY alloy, the MPEA exhibits 59% lower in thermally grown oxide (TGO) growth rate, as well as negligible TGO spallation after 500 h at 1200°C. This performance stems from a significantly refined eutectic structure enabling rapid formation of a protective Al ₂ O ₃ scale during initial oxidation, coupled with lattice distortion that elevates vacancy formation energy and Al migration barriers within the Al‐depletion zone (ADZ), drastically reducing sustained diffusion rates. This co‐design strategy, integrating tailored microstructure and lattice distortion, establishes a new paradigm for ultra‐stable performance in extreme environments.