Development and characterization of a high-Cr-content Co–Ni–Al–V–Ta–Cr superalloy: Microstructure, mechanical properties and oxidation resistance

• Developed a novel Co–30Ni–10Al–5V–4Ta–12Cr superalloy with a stable γ/γ′ two-phase structure and high Cr content for enhanced oxidation resistance. • Achieved a high γ′ solvus temperature of 1139°C, low density of 8.48 g/cm3, minimal γ/γ′ lattice misfit of +0.28%, and high compressive yield strength of 651 MPa at 800°C. • Demonstrated excellent oxidation resistance with a weight gain of 6.5 mg/cm3 after 200 h at 1000°C, attributed to a complex oxide scale including outer and inner mixed oxide layers. • Utilized the CALPHAD method for thermodynamic design and phase stability assessment, proving its effectiveness in optimizing high-Cr Co-based superalloys.