Ductility of Ni3Al doped with substitutional elements

This paper reports on ductility of B-free Ni3Al alloys. Recrystallized Ni3Al binary alloys with Ni-rich compositions show appreciable ductility when an environmental effect is eliminated, while the alloys with stoichiometric and Al-rich compositions remain brittle. The ductility in the Ni-rich Ni3Al alloys is associated with low ordering energy. The additions of ternary elements, which are classified as γ formers, ductilize ternary Ni3Al alloys(Ni-23 at% Al-2 at% X, X = Pd, Pt, Cu and Co), whereas the additions of γ' formers embrittle ternary Ni3Al alloys(Ni-23 at% Al-2 at% X, X = Ta, Mo, Nb, Zr, Hf, V, Ti and Si). The additions of small amounts (less than 1 at%) of γ' formers such as Zr and Hf also ductilize as-cast ternary Ni3Al alloys. Ductility of Ni3Al alloys doped with substitutional elements is discussed in terms of ordering energy and microstructure