Investigation of Stress Corrosion Cracking in rocks, a reactive molecular dynamic simulation

Stress corrosion cracking (SCC) is a chemically activated mechanism involving the adsorption of fluids on crack surfaces and the propagation of fluid-assisted cracks. In most cases, the underground rock is saturated with fresh or saltwater. To prevent SCC and predict the lifetime beyond which SCC may fail, we need to understand SCC's atomic mechanisms. In this study, stress corrosion cracking of the pre-cracked crystalline quartz is considered using a reactive molecular dynamics simulation. The results show that water has a strong influence on subcritical crack growth such that the speed of crack growth caused in water is higher than the crack velocity in the dry ambient. Crack failure in the wet condition is related to the Si-O bond-breaking followed by the formation of silanol (Si-O-H) group. In this regard, when the Si-O bond is broken, a chemical reaction between Si and OH bonds occurs, which causes a reduction in the quartz's surface energy.