The influence of temperature on the mechanical properties of polycrystalline and single-crystalline Ni₃Al

Abstract Because of the excellent mechanical property at high temperature, single-crystalline Ni3Al-based alloys, which belong to Ni-based superalloys, are widely adopted in the fields of aerospace, aviation and military. Usually, single-crystalline Ni-based alloys are bonded or welded together by polycrystalline Ni-based alloys. In this study, the Young’s modulus, shear modulus, bulk modulus, and Poisson ratio of polycrystalline Ni3Al at the temperature ranging from 10 °C to 850 °C were calculated according to Voigt–Reuss approximation, and the relationships between the mechanical properties and the temperatures were clarified. Moreover, the influence of temperature on the universal anisotropy index and mechanical properties of single-crystalline Ni3Al was evaluated. Results show that, except for Poisson ratio, the increase of temperature linearly decreases the mechanical properties of polycrystalline Ni3Al, while it increases the universal anisotropy index of the single-crystalline Ni3Al. Moreover, different with the bulk modulus, the Young’s modulus and shear modulus of single-crystalline Ni3Al are obvious anisotropic, and their anisotropic characteristics are quite opposite. The increasing temperature decreases both maximum and minimum values of Young’s modulus, shear modulus, and bulk modulus of single-crystalline Ni3Al.