A first-principles study on D022 precipitation phases of Ni-based superalloys with loading stress and high temperature

Abstract

A first-principles study on Ni-based superalloys is performed to estimate the properties of D022 structure Ni3X (Ni3Nb, Ni3Ta, Ni3V) phases and L12 structure Ni3Al phase with loading stress and high temperature. By stress-strain curve, the strength is higher in D022 structure Ni3X than in L12 structure Ni3Al. Loading stress causes systems unstable to increase decomposition tendency through calculating enthalpy and E above hull. The elastic properties reflect stress decreases system modulus and increases anisotropy. The lattice misfit is affected by stress and temperature. Loading stress increases lattice misfits of D022 structure Ni3X. Raising temperature decreases lattice misfit of each system. The effect on lattice misfit is larger in stress than in temperature. Ni3V can form negative lattice misfit with high temperature and low stress. Through overall comparison, the D022 Ni3V has advantages on high mechanical resistance, high thermodynamic stability, excellent elastic properties, negative lattice misfit in condition of high temperature and loading stress, which can be used to develop a new precipitation strengthening Ni-based superalloy.