Abstract
Torsion fatigue tests were conducted for smooth bars and circumferentially notched bars of Ti-6Al-4V alloy. The purpose of this work is to evaluate fatigue strength and notch sensitivity under stress concentration factors of Kt=2.0 and 4.0. Fatigue life and fatigue strength decrease with increasing stress concentration. To investigate the crack initiation and propagation, the crack length were calculated with Hooke's law. When compared at the same fatigue life, the crack initiation life for Kt=4.0 was much shorter than that for Kt=2.0. Difference of the fatigue fracture mechanisms between blunt and sharp notch is considered to cause this phenomenon. Under low stress amplitude, the crack propagates under tensile mode toward a 45° to the axial direction. The crack propagated all over the blunt notch, and the crack propagated in the cross section of the sharp notch root under low stress amplitude. As a result, the fracture surface of blunt notch specimen under low stress amplitude was flat, and that of sharp notch specimen showed factory-roof pattern. The formation of factory-roof increases contact areas in the fractured surface and lengthens crack propagation time.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: The Proceedings of the Materials and Mechanics Conference
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.