Single crystal growth and characterization of binary stoichiometric and Al-rich Ni 3Al

Abstract

Binary stoichiometric Ni 3Al (Ni–25 at% Al) single crystals and Al-rich single-crystal-like (Ni–26 at% Al, Ni–27 at% Al) alloys that do not contain any ternary additions have been successfully grown for the first time, by using the floating zone method. The quality of the crystals was examined by the Laue X-ray back-reflection method and optical microscopy. The stoichiometric single crystals had good crystallinity. The Al-rich crystals consisted of single crystalline Ni 3Al matrix and NiAl precipitates. The compressive yield strength of the crystals was evaluated for [0 0 1]-orientation in the temperature range of 293–1273 K. Among the crystals studied the stoichiometric Ni 3Al single crystals exhibited the highest yield stress (850 MPa) at 1073 K, which is almost two times larger than that of polycrystalline Ni 3Al.