Notch size effects in HCF behavior of Ti-6Al-4V

The high cycle fatigue (HCF) behavior of Ti-6Al-4V is investigated for cyli ndrical specimens having three sizes of geometrically similar circumferenti al V-notches, each with an elastic stress concentration factor, K-t, of app roximately 2.78. A step loading technique for obtaining a point on a consta nt life (10(6) cycles) Haigh diagram from a single test specimen was implem ented. Tests were performed at stress ratios of R = 0.1, 0.5, and 0.8 for s pecimens machined from two different product forms of Ti-6Al-4V, bar and pl ate forgings. Results indicate that while there is a definite notch size ef fect in the Ti-6Al-4V bar within the range of notch sizes tested, little or no such effect exists in the plate. (C) 1999 Elsevier Science Ltd. All rig hts reserved.