Microstructure and mechanical property in dual two-phase intermetallic alloys composed of geometrically close-packed Ni 3X (X: Al and V) containing Nb

Abstract

Dual two-phase intermetallic alloy, which is composed of Ni 3Al (L1 2) and Ni solid solution (A1) phases at high temperature and is refined by a eutectoid reaction during low temperature aging, was prepared on the basis of the Ni 3Al–Ni 3Nb–Ni 3V pseudo-ternary alloy system. The eutectoid reaction decomposes the A1 phase to a mixture of geometrically close packed (GCP) structures of Ni 3Al (L1 2) and Ni 3V (D0 22). Dual two-phase intermetallic alloys were characterized by scanning electron and transmission electron microscopy. High-temperature compression and tensile tests, and compression creep test were conducted. It was found that the dual two-phase intermetallic alloys showed high yield and tensile strength with good temperature retention, accompanied with reasonable tensile ductility. The dual two-phase intermetallic alloys showed lower creep rate than conventional Ni-base superalloys. Also, the present two-phase intermetallic alloys are superior to the counterparts containing Ti, and they are promising for the development of a new-type of high-temperature structural material.