A continuum damage mechanics model for failure of metals in high temperature environment

An advanced creep modeling, based on dislocation mechanics and incorporating damage effects, is developed at continuum scale. In the proposed formulation creep damage does not depend on time (time independent damage formulation) but on the accumulated creep strain. Thus, tertiary creep stage can be predicted as the evolution of the secondary stage in which the current stress is increased by damage effects in addition to geometry modifications. The proposed approach extends the initial continuum damage mechanics approach proposed by Kachanov in order to have a more explicit correlation between material creep response, damage mechanics and material microstructure. The possibility to account for microstructure modifications due to solid solutions kinetics though the identification of the damage parameters evolution laws is given. An example of the applicability of the proposed model to IMI834 titanium alloy is given