Abstract
This study was conducted to examine the effect of a hybrid surface modification on the fatigue strength of Ti-6Al-4V alloy. The hybrid surface modification was composed by plasma carburizing and WPC treatment. In the case of the carburized alloy, cracks were initiated from the compound layer at relatively low stress amplitude level, so that there was no improvement in the fatigue strength. However, when the alloy was further WPC-treated, the brittle compound layer was eliminated and compressive residual stress was introduced. As a result, the initiation site of cracks was moved to the inside under the hardened case and the fatigue strength was significantly improved. The results showed that the hybrid surface modification method estimated in this study can improve the fatigue strength of the titanium alloy as well as the wear resistance.
