EFFECTS OF TENSILE STRENGTH ON FATIGUE BEHAVIOR AND NOTCH SENSITIVITY OF Ti-6Al-4V

In this research, rotating bending fatigue test at minimum to maximum stress ratio of R=-1 was used for investigating the fatigue behavior of Ti-6Al-4V alloy. Both smooth and notched specimens, with elastic concentration factor, kt, of approximately 3.6 and 4.1 were used for this purpose. In addition, the effect of variation in ultimate tensile strength, UTS, on the fatigue behavior of this alloy was studied. S-N curves were drawn and the value of notch sensitivity was obtained for each case. The results showed that the presence of notch in Ti-6Al-4V alloy has a different amount of sensitivity when the notched specimens were subjected to high cycle fatigue (HCF) and low cycle fatigue (LCF) tests. However, the notch sensitivity of this alloy was shown generally to be much lower than steel alloys with similar UTS values. Thus, considering the high compatibility of this alloy with the body environment and its low sensitivity to notch, one can strongly recommend this alloy for use in biomedical application.