关键词: “团簇加连接原子”模型, 镍基高温合金, Nb, Ta, 错配度, γ′相, 力学性能

Abstract: Based on the ideal composition formula of Ni-based superalloys [Al-Ni₁₂](Al, Cr)₃determined by the cluster-plus-glue-atom model, the microstructure and mechanical properties of the alloys replaced Ti by Nb and Ta were investigated by X-ray diffraction, scanning electron microscopy, hardness and compression testing. The results show that with the addition of Nb and Ta elements, the morphology of γ′ phase changes from spherical to cuboidal with rounded corners, the size and volume fraction of γ′ phase increase first and then decrease, the lattice parameters of γ phase increase, the lattice parameters of γ′ phase increase first and then decrease, and the absolute misfits of γ/γ′ are enlarged. The hardness and yield strength of the alloy are increased by adding Nb and Ta elements. When Nb and Ta are added simultaneously and Ti replaces Mo, the alloy has the highest hardness of 464 HV5 and the highest yield strength of 1043 MPa.

Key words: cluster-plus-glue-atom model, Ni-based superalloys, Nb, Ta, misfit, γ′ phase, mechanical properties