The Effect of High Temperature Oxidation on the Fatigue Fracture Mechanism of Ti-4Al-2V Alloy

摘要

The effect of high temperature oxidation on high cycle fatigue fracture mechanism of Ti-4Al-2V alloy was investigated. The fatigue coupons were oxidized at different temperatures in air for 2 hours. Some of them were annealed at lower oxygen pressure (10-5 torr) in the vacuum furnace. The high cycle fatigue (HCF) tests were performed under bending and rotating loadings. The experimental results were analyzed and S-N diagrams were plotted. The fatigue fracture mechanisms were studied with SEM. The results showed that fracture mechanism change during the oxidation, specifically during the vacuum annealing. Vacuum annealing treatment after the high temperature oxidation not only alters the fatigue fracture mechanism,but also improves the fatigue endurance limit.