Accurate determination of creep cavity nucleation rate and growth rate with considering the partial coalescence prior to rupture and its impact on creep lifetime prediction

In high-temperature applications such as power generation and aerospace, understanding material failure due to creep deformation is crucial, especially for components like jet engine compressor blades and steam turbines. This study investigates the evolution of creep cavitation damage, focusing on cavity nucleation, growth, and coalescence in the material's microstructure. Beyond nucleation and growth, this study investigates cavity coalescence, an inevitable process leading to microcracks and macrocracks. It captures the evolution of exact cavity measurements. This mechanism is associated with an increasing nucleation rate and a decreasing growth rate of individual cavities. Enhancing the accuracy of tensile creep behaviour models, this study extends the cavitation model initially proposed by Riedel and calibrated by Qiang Xu. It addresses cavity coalescence during late-stage rupture using high-fidelity experimental data and a modelling approach. A spherical reconstruction hypothesis for cavity coalescence is proposed and validated with cavitation data from the brass alloy Cu-40Zn-2Pb. The model demonstrates accuracy for lifetime modelling with an increase of accuracy from traditionally 45–83% and a coefficient of determination from 0.767 to 0.997, highlighting its robustness for describing coalescence and aiding in design and maintenance assessments.