Fabrication and Characterization of Co‐Based Medium‐Entropy Alloys for Structural and Functional Applications: A Comprehensive Review

Co‐based medium‐entropy alloys (MEAs) have attracted considerable interest in materials science due to their excellent mechanical properties, thermal stability, and superior resistance to oxidation, corrosion, and wear. These alloys, characterized by a balanced composition of multiple principal elements, exhibit remarkably high‐temperature strength, making them suitable for aerospace, energy, and biomedical applications. Various synthesis methods, including arc melting, powder metallurgy, additive manufacturing, and mechanical alloying, have been explored to optimize their microstructure and enhance performance. Despite their promising advantages, Co‐based MEAs face several challenges, such as high material and processing costs, limited ductility, and difficulties in large‐scale manufacturing. Additionally, sustainability concerns related to cobalt extraction and alloy recyclability require further research to develop eco‐friendly processing and recovery methods. This review comprehensively analyzes the fabrication techniques, microstructural characteristics, mechanical and thermophysical properties, and potential applications of Co‐based MEAs. Furthermore, it discusses the existing challenges and future research directions, including alloy design strategies, advanced processing techniques, and sustainable manufacturing approaches. By addressing these challenges, Co‐based MEAs have the potential to revolutionize high‐performance materials for next‐generation structural and functional applications.