High-entropy alloys (HEAs) have emerged as a transformative class of materials characterized by multi-principal-element compositions and complex solid-solution structures. Their unique combination of high configurational entropy, sluggish diffusion, and lattice distortion offers exceptional thermal stability, mechanical strength, and oxidation/corrosion resistance. These properties make HEAs promising candidates for structural applications under extreme conditions, including high temperature, high stress, radiation, and corrosive environments. HEAs operating under extreme thermal environments are subjected to complex microstructural evolutions, phase transformations, aggressive oxidation or corrosion, and long-term degradation processes—often under coupled thermomechanical and chemical effects that significantly accelerate damage evolution. Understanding the degradation mechanisms and optimization the alloy design to improve the oxidation resistance, microstructural stability, service life of these HEAs under extreme atmospheres is essential for ensuring the safety, reliability, and performance of high-temperature materials and components.

This Research Topic aims to bring together Original Research and Review articles that advance the fundamental and applied understanding of HEAs used in high-temperature environments. We invite contributions that explore the mechanisms of thermally induced oxidation/corrosion, microstructural evolution, phase stability and transformation under coupled thermal and mechanical loads, as well as the design and fabrication of novel HEAs tailored for high-temperature environments. We particularly seek studies that integrate rigorous experimentation (including in-situ methods) with theory, simulation, and data-driven approaches to reveal degradation mechanisms of HEAs. Special emphasis is placed on studies addressing oxidation and corrosion mechanisms, thermo-mechanical interactions, and environmentally assisted degradation.

Topics of interest include, but are not limited to:
1. High-temperature oxidation and corrosion behavior of HEAs under different environment (e.g., dry air, steam, CO₂, liquid metal, molten-salt).
2. The roles of selective oxidation and reactive-element effects during the oxidation of HEAs.
3. Phase transformations and microstructural evolution of HEAs under thermal exposure.
4. Failure analysis and degradation mechanisms under coupled loads (creep/fatigue–oxidation interactions, thermomechanical cycling, and environmentally assisted cracking).
5. In-situ and advanced multiscale characterization techniques for oxidation/corrosion testing.
6. Computational and multiscale modeling of oxidation and degradation under high-temperatures.
7. Design and development of high-performance HEAs under high-temperatures.

This Research Topic seeks to foster interdisciplinary collaboration and promote cutting-edge research that supports the development of durable, high-performance HEAs capable of withstanding the demanding conditions of modern high-temperature applications.

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Oxidation and Degradation of High-Entropy Alloys under High-Temperatures