Peridynamic Simulation of Crevice Corrosion in a Titanium Alloy upon Exposure to a Marine Environment

The numerical simulation of crevice corrosion of a titanium alloy upon exposure to an aggressive marine environment is presented and discussed. The model parameters were calculated using the IR voltage theory and a one-dimensional calibration peridynamic model. The values of pH inside the crevice, having openings of 0.01, 0.05 and 0.1 mm, were calculated. A crevice corrosion simulation model, for a crevice of 0.01 in width and 4.95 mm in depth, was built, and a full-scale simulation was conducted using the model. Experiments were conducted to verify the simulation results. The chosen test pieces having crevice openings of 0.01, 0.05 and 0.1 mm were soaked in EXCO solution of 65 °C for 5, 10 and 15 days. The test results showed the pH inside the crevice initially decreased with depth and reached a minimum value when the titanium ions were saturated. Thereafter, the value of pH increased with depth. Comparing results of the simulation with experiment, results of corrosion depth within the crevice were in good consistence. Depth of pits as a direct consequence of crevice corrosion had an exponential relationship with distribution of pits. The IR voltage decrease was proven to be an important factor that exerts an influence on depth of corrosion due to crevice corrosion.