| Abstract Scope |
Developing new alloys that operate beyond the temperature limits of Ni-based superalloys is critical for energy sustainability, where materials must endure extreme environments of heat, stress, and oxidation. Refractory complex concentrated alloys (RCCAs) are promising due to their high melting points and strength at elevated temperatures. However, achieving a balance between room-temperature ductility and high-temperature creep strength remains challenging. Many (Mo, W, Hf, Zr)-rich RCCAs possess high compressive strength but lack tensile ductility, limited by grain boundary embrittlement from oxides and phase decomposition. Conversely, ductile NbTaTiHf-based RHEAs exhibit poor creep resistance due to insufficient high-temperature strength under screw dislocation glide. Dispersion-strengthened, edge dislocation glide-controlled ductile RHEAs appear most promising for combining phase stability, creep strength, and recrystallization resistance. Furthermore, most RCCAs suffer from inadequate oxidation resistance, underscoring the need for advanced protective coatings to enable long-term high-temperature performance. |