Mechanism of crack evolution and strength failure in chemo-mechanical induced fracture

Chemo-mechanical coupled fracture is ubiquitous among various application fields. Under-standing the mechanism of crack propagation is critical to the prediction and control of fracture behavior. In this paper, mechanical damage and chemical erosion have been investigated by a combination of experiments and theoretical analysis. We developed a theoretical model to analyze the interface evolution and the mechanical state of the crack tip in chemically active environments based on the transition-state theory. This model enables us to predict mechanical failure and chemical corrosion of materials exposed to external acid attack. Theoretical pre-dictions of the corrosion rate and fracture strength have been validated by fracture experiments performed in corrosive solutions of different concentrations. In particular, we discovered a non -monotonic and non-linear relationship between the degree of corrosion and fracture strength, which demonstrates that corrosion-induced crack tip blunting and mass loss of materials together affect the cracking critical state. We further conducted the thermodynamic analysis of a quasi -static cracked body to investigate the effect of corrosion on energy stored in the crack tip. Our theory-experiment-combined study reveals the mechanism of coupling chemical and mechanical damage, which provides significant insight into corrosion-induced fracture behavior in aggressive environments.