Effect of elastic stress on the electrochemical corrosion behavior of TA2 titanium in 3.5% NaCl solution with different pH

• In situ electrochemical testing under stress loading was successfully conducted. • The influence of stress on the corrosion process of TA2 was identified. • The results demonstrated the effect of stress on the properties of TA2 oxide film. • Utilizing the PDM model, the impact of stress on the corrosion behavior of TA2 was described. The synergistic effect of applied elastic stress and pH on TA2 corrosion was investigated using in-situ electrochemical techniques. The results demonstrate that elastic stress accelerates the corrosion of TA2 and alters the corrosion mechanism, as evidenced by changes in electrochemical impedance spectroscopy (EIS) plots from two to three time constants. Furthermore, elastic stress deteriorates the passive film, leading to a threefold increase in donor density under stress compared to non-stressed samples and a heightened susceptibility to pitting corrosion. Wavelet transform analysis of electrochemical noise (EN) data reveals that the non-stressed sample is governed by long-time scale processes, while the maximum relative energy shifts from d 8 to d 1 upon the application of stress. Microstructural characterization confirms the electrochemical findings, indicating that pitting occurs not only in the Fe-rich phase and grain boundary under stress but also within α phase. The maximum depth of the pitting pit under stress (approximately 429 nm) is more than twice that of the non-stressed sample (approximately 169 nm). The setup for in-situ electrochemical measurements under various stresses was successfully established. The synergistic effect between the applied elastic stress and solution pH on TA2 was evaluated by electrochemical measurements. The results indicated that the elastic stress accelerates the corrosion of the TA2 and alters the corrosion process. The Bode plots in the EIS results varied from two to three-time constants. Mott-Schottky analysis demonstrated that the passive film exhibited n-type semiconductive property under different conditions. Under elastic stress, the donor density increased to three times that of the non-stress sample, resulting in a more defective passive film. EPN analysis revealed that the maximum energy value shifted from d 8 to d 1 under the stress, enhancing pitting corrosion control. In non-stressed samples, pitting holes preferentially appeared at the Fe rich phase and grain boundaries; however, this selective dissolution weakened under applied stress, allowing pitting holes to develop in the α phase. This study provides a theoretical foundation for understanding the influence of elastic stress on the actual corrosion process of TA2 in marine environments.