High-temperature alloys: Recent advances from conventional alloys to complex concentrated systems
Yanying Li, Hao Lv, Yuan Qian, Jun Tan, Zhongxue Feng, Zhaosong Chen, Jianwei Xu
Abstract
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.