A multiaxial creep-damage model for creep crack growth considering cavity growth and microcrack interaction

•A new multiaxial creep ductility factor based on cavity growth theory is proposed.•Multiaxial creep ductility model is validated by theoretical solutions and test data.•The influence of microcracks is considered in the creep constitutive equations.•2-D and 3-D FE analyses are performed based on the proposed creep-damage model.•The proposed creep-damage model shows an excellent predictive capability.

This article presents a concise multiaxial creep-damage model for creep crack growth considering the cavity growth and microcrack interaction. Special emphasis is put on developing and validating the multiaxial creep ductility factor (MCDF) based on power-law creep controlled cavity growth theory. Good agreements with the theoretical and experimental data prove the effectiveness of the proposed MCDF. The application of the proposed creep-damage model through finite element simulation of the creep deformation and crack growth in C-Shaped Tension and Compact Tension specimens of 316H tested at 550 °C confirms the predictive capability of the proposed model.