An Entropy-Based Damage Model to Assess the Creep Behaviour of Nickel-Based Superalloys

Unified mechanics theory employs an entropy-based damage parameter (known as thermodynamic state index) to track damage in a material that is subjected to variety of mechanical, thermal, electrical and other kinds of loads. The fundamental and consistent approach followed in defining and in evolving this “thermodynamic state index” enables reliable estimation of material damage, even when multiple competing damage mechanisms are involved. In this paper, uniaxial creep behaviour of Inconel 600 nickel-based superalloy is modelled by modifying the Norton power law for creep to accommodate the entropy-based damage parameter. The resulting model is calibrated and verified using available uniaxial tensile creep data at different creep loads.