Constitutive Modeling of Hardening and Creep Response of a Nickel-Based Superalloy Udimet 720Li

Based on uniaxial experimental data of a nickel-based superalloy Udimet 720Li under monotonic tension, symmetrically cyclic loading and creep loading, the paper studied to utilize the Bodner-Partom unified constitutive theory to model the mechanical behaviors of the material under these three different loading conditions for the first time. After detailed analysis of the constitutive characteristics of the unified equations, a systematically optimized strategy was proposed to obtain material parameters in the equations. Thereafter, the B-P model was implemented into ABAQUS through UMAT subroutine and was employed to calculate inelastic responses of the material for different uniaxial loading cases at 700°C. Theoretical predictions are compared to experimental data and good agreement is generated.