Isothermal tensile, cyclic behaviour and constitutive modelling of nickel-based directionally solidified superalloy

Constitutive modelling is one of the main constituents of fatigue life estimation methodology. It provides the correct approximation of stress and strains at the critical location of structures. The coded phenomenological constitutive models can be integrated into the finite element software using user material subroutines, which characterize the material behaviour on structure scale in accordance with the industrial requirement. A nickel-based DS superalloy DZ125 has been experimentally scrutinized for the influence of temperature and orientation on the tensile and viscoplastic behaviour of the material, modelled by chaboche-based unified viscoplasticity model that also account for orientation dependent anisotropy. The constitutive model is compiled into UMAT for its implementation in FEA software ABAQUS. Parameters are optimized based on the tensile, cyclic and stress relaxation behaviour of the material. The simulation results manifests the capability of the modified model for characterizing the tensile and fatigue behaviour of directionally solidified superalloy DZ125, and matiching the experimental results.