|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Fatigue in Materials: Fundamentals, Multiscale Modeling and Prevention
||Analysis of Crack Initiation and Early Growth in Ti Using Miniaturised Ultrasonic Fatigue Testing
||Arutyun Arutyunyan, Jicheng Gong, Angus J. Wilkinson
|On-Site Speaker (Planned)
We have been using 20 kHz ultrasonic vibration of excite bending modes in small 100-200 μm wide cantilevers in thin foils of commercially pure Ti (grade 2) so as to study the development of fatigue damage. Dynamic elastic finite element analysis was used to design an hourglass sample shape producing a relatively uniformly stressed region near the stress peak in the narrowest section. The samples are monitored in situ using optical microscopy including crossed linear polarisers to reveal grain contrast in Ti and cracks/slip bands within the microstructure. An automated procedure has been developed to apply blocks of loading cycles interspersed with collection of optical micrographs. EBSD measurements before testing allow the crack path and growth rate along that path to be correlated with grain orientations and grain boundary misorientations which control the availability of slip systems and extent of crack plane twist and tilt deflections at grain boundaries.
||Planned: Supplemental Proceedings volume