Abstract
Three model binary Ti-Al alloys with single α phase were investigated in this study to develop a fundamental understanding of high cycle and very high cycle fatigue behavior in α-titanium alloys. Ultrasonic fatigue instrumentation with a cyclic frequency of nominally 20 kHz was used for fully reversed loading fatigue testing and combined with customized optical microscopy to study small crack growth from artificial cracks initiated at micro-notches produced by focused ion beam. Fractography showed the formation of low ΔK facets with different features near the crack initiation sites. Micro-beach marks were observed to form on some facets which could be correlated with the spatial angle between facet normal and loading direction. Aluminum content and processing (forging/rolling history) were found to have no significant effect on the small crack growth behavior of the studied alloys. Different crack growth models were compared and discussed to estimate the fatigue performance, especially for cross-rolled Ti-4Al alloy with void-type defects.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
