Abstract:The creep behaviors of the Ni-added Ir₈₅Nb₁₅ alloys were investigated at 1650～1800℃ by compression tests in vacuum. X-ray diffractometry, transmission electron microscopy and scanning electron microscopy we re conducted to characterize the microstructure and lattice misfit change by the addition of Ni in the Ir₈₅Nb₁₅ alloy. The results reveal that the Ni addition has a significant effect on the creep resistance of the Ir₈₅Nb₁₅ two-phase refractory superalloys. Basing on the results, the relationship among the Ni addition, lattice misfit, microstructure development, and the creep behavior in the Ni-added Ir₈₅Nb₁₅ alloys is discussed.

Key words: refractory superalloy; microstructure; lattice misfit; creep behavior