Abstract: Nitride-reinforced (HfNbTaTiV)₉₀N₁₀ high-entropy alloy aiming at high-temperature applications is designed in this paper. Abundant FCC nitride phases are formed in situ in theBCC matrix by arc melting technique, without complex deformation or heat treatment. The (HfNbTaTiV)₉₀N₁₀ alloy exhibits a remarkable yield strength of 2716 MPa and ultimate compressive strength of 2833 MPa with a plastic strain of 10% at room temperature. Besides, the alloy remains a high yield strength of 279 MPa at 1400 °C. The nitride phases play an essential role in maintaining the excellent strength-ductility combination at room temperature and enhancing the high-temperature softening resistance. Alternating BCC and FCC phases possess the semi-coherent interface, which not only strengthens the BCC matrix but also promotes the compatible deformation of the duplex microstructure. The lattice coherency structure of the semi-coherent interface is conducive to the slip transfer of partial dislocations through the interface, which facilitates the accommodation of plastic deformation. The cross-slip of the screw dislocations effectively eliminates stress concentration and leads to good ductility of the dual-phase alloy. The results demonstrate that the nitride phases achieve coordinate deformation with the matrix without deteriorating the ductility of the (HfNbTaTiV)₉₀N₁₀ alloy.

Key words: Nitride-reinforced, High-entropy alloy, Softening resistance, Strength-ductility balance, Semi-coherent interface