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.