To improve the design and safety of power plant components, long-term hightemperature creep behaviour of a power-plant material, such as Cr-based alloy, should be
assessed. Prior studies indicate that power-plant components undergo material degradation
and premature failure by nucleation, growth and coalescence of microvoids as a result of
creep damage. In classical crystal-plasticity-based models, a flow rule and a hardening law do
not account for global stiffness degradation of materials due to evolving microvoids, having a
significant influence on material behaviour, especially under large deformations. In this study,
a crystal-plasticity scheme coupled with an appropriate continuum damage model is
developed to capture the anisotropic creep-damage effect on the overall deformation
behaviour of Cr-based power-plant steel. Numerical simulations show that the developed
approach can characterize creep deformation of the material exposed to a range of stress
levels and temperatures under consideration of stiffness degradation under large deformation
