Local kinetics of cavitation in hydrogen-exposed EPDM using in-situ X-Ray tomography: Focus on free surface effect and cavity interaction

Decompression failure in high-pressure gas exposed rubbers has almost only been studied at a global scale so far. In the present study in hydrogen-exposed EPDM, the growth kinetics of cavities was visualized and quantified at the cavity scale using 3D in-situ X-ray micro-tomography with an emphasis on interaction effects and boundary conditions. The volume evolution of cavities was processed and the inflation rate and maximum volume were calculated. The boundary conditions of selected cavities was analysed in terms of distance to the free surface as well as distance to other cavities. Proximity to the free surface was found to be a driving force for evolution of cavities up to a certain range beyond which the growth kinetics are more driven by other factors such as time of nucleation. Within the range made accessible by the current spatial resolution, no clear interaction effect was pointed out between close cavities.