Effect of thermal oxidation process on fatigue behavior of Ti-4Al-2V alloy

In this study, the effect of thermal oxidation (TO) process on fatigue behavior of Ti-4Al-2V alloy has been examined. To do so, rotary bending fatigue experiments were performed on the base alloy samples before and after oxidation at 600 and 750 °C for 2 h. Comparison of S-N curves revealed that, relative to base alloy samples, fatigue limit of oxidized specimens was a little increased at 600 °C and then sharply decreased at 750 °C. While X-ray diffraction (XRD) studies of the oxide layer formed at 600 °C could not revealed any crystal structure due to possibly its low volume fraction but a fine oxide layer of rutile (TiO2) was detected on the XRD pattern of the oxidized samples at 750 °C. The results of present study showed that, oxidation process has considerable effect on fatigue crack initiation process.