Microstructure and mechanical properties of dual two-phase Ni sub(3)Al-Ni sub(3)V intermetallic alloys charged with carbon

The microstructures and mechanical properties of ternary (Ni sub(75)Al sub(9)V sub(1 6)) and multicomponent (Ni sub(69)Al sub(9)V sub(9 .5)Nb sub(3)Ti sub(1.5) Co sub(4)Cr sub(4)) dual two-phase intermetallic alloys charged with C were investigated by scanning electron microscope, electron probe microscopic analyzer, x-ray diffraction, Vickers hardness, and tensile tests. Solid solubility limits of C in the dual two-phase microstructures were small, mostly less than 0.1 at.%. When C was charged exceeding the solid solubility limit, large-sized carbides were solidified with no structural coherency with the dual two-phase microstructure. Major transition metals constituting the carbides changed from Nb and Ti to V with increasing charged C content. This transition was correlated with the capability of the carbide formation. C dissolving in the dual two-phase microstructure enhanced hardness and flow strength through solid solution hardening without sacrificing tensile ductility. The formed carbides little contributed to strengthening, rather, contributed to softening through depleting constituent element V as well as alloying metals Nb, Ti, and Cr from the dual two-phase microstructures.