Shot peening effects on corrosion behavior of commercial pure titanium in body simulating solution

Abstract

In this study, the effect of shot peening on the corrosion behavior and the microstructure of commercial pure titanium was studied. The experiments including measuring the compressive residual stresses created by shot peening using steel balls (0.3 mm in diameter) and the durations of 20 and 60 s as well as the intensities of 0.8 and 0.1 mm Almen, and the electrochemical corrosion tests after 1, 4, and 7 days of immersion were carried out. The studies performed showed that, with an increase in the shot peening duration and the shot peening intensity or both, the compressive residual stress increased at the sample surface. The highest amount of residual stresses was in the T3 sample, which exhibited the lowest depth, as well. The results of the electrochemical impedance spectroscopy of the original (non-shot-peened sample) sample and the shot-peened samples after 1, 4 and 7 days of immersion in the Ringer’s body simulator solution showed that the samples with the highest intensity or the longest shot peening duration showed better corrosion behavior compared with that of other parameters and the original sample. As the immersion time increased, the impedance values increased and as a result, the electrochemical behavior of the samples improved. The polarization tests after seven days of immersion in Ringer’s solution showed that the potential of the shot-peened samples was more positive. Also, the lowest corrosion current density was obtained in the T3 sample with the highest compressive residual stress.