High-temperature alloys: Recent advances from conventional alloys to complex concentrated systems

This study systematically reviews strengthening mechanisms and fabrication technologies of high-temperature alloys from conventional systems to complex concentrated alloys (CCAs). The dual-phase control in Ni/Co/Fe-based alloys and CCAs is shown to achieve performance enhancement through synergistic solid-solution strengthening and precipitation strengthening. Advanced processing routes (including vacuum induction melting-electroslag remelting-vacuum arc remelting triple smelting, powder metallurgy, and laser additive manufacturing) are demonstrated to refine alloy purity, eliminate macro-segregation, and enable near-net shaping of complex components. Comparative analysis reveals that Ni/Co/Fe-based alloys maintain a yielding strength >500 MPa below 1000 °C, Mo-based alloys stabilize at 1000–1600 °C, W/Ta-based alloys retain structural integrity >1600 °C, while CCAs exhibit unprecedented ultimate tensile strength >1800 MPa across 25–1700 °C via multi-principal element interactions. To address hypersonic and deep-space extreme conditions, critical challenges are identified: extending second phase stability beyond 1200 °C, developing thermomechanical-oxidation coupled damage models, and implementing multiscale microstructure regulation. This work establishes a theoretical foundation for designing next-generation alloys with targeted performance under extreme service environments.