The Development of a Cavitation-Based Model for Creep Lifetime Prediction Using Cu-40Zn-2Pb Material

The occurrence of creep induced cavitation can considerably shorten the lifespan of numerous high-temperature applications. A contemporary problem in structural mechanics and materials science is the inadequate mathematical description of creep deformation and rupture time. This situation stems not only form a lack of accurate quantification and incorporation of cavitation damage in current theoretical models, but it is compounded by the strong stress level dependency of the creep lifetime. Cavitation is the rate-controlling mechanism during creep. To this end, this study has developed a cavitation-based method for creep rupture lifetime prediction. For accuracy and a representative data, cavitation data measured using x-ray synchrotron tomography, are chosen for the study. Cavitation damage modelling precisely cavity nucleation, growth and size distribution are presented. Functional relationships between creep exposure time and cavitation damage are developed to aid creep lifetime prediction. This approach has the advantage of traceability as it is developed based on quantifiable physical changes in the material (cavity nucleation and growth). This study reports the latest progress in the development of a cavitation model for a specific material under testing condition. It is planned to incorporate it, to develop a creep lifetime prediction and extrapolation model. This paper offers a theoretical foundation for a time-based extrapolation method to predict creep lifetime. Furthermore, the cavitation modelling approach used in this study may be applied in other failure modes like fatigue.