|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Fatigue in Materials: Fundamentals, Multiscale Modeling and Prevention
||L-71: Crack Initiation in a Ni-based Superalloy Studied by Miniaturised Ultrasonic Fatigue Testing
||Jicheng Gong, Isaac Cabrera,
|On-Site Speaker (Planned)
Laser micro-machining has been used to cut meso-scale ~100-200 Ám wide cantilevers in thin metallic foils. Cyclic deflections of the cantilevers were excited through vibration of the sample using a high power ~20 kHz ultrasonic generator. The meso-cantilevers were machined so as to randomly sample relatively small patches of microstructure in polycrystalline Ni-superalloy foils. An optical microscope integrated with the loading system enabled in situ monitoring of the sample surface and fatigue damage was recorded throughout each test. SEM images and EBSD maps of the entire tested region were obtained prior and/or post testing. The formation of localised slip and profuse surface extrusions associated with crack initiation was recorded, and locations correlated with underlying microstructure. Annealing twins were present in large numbers and fatigue damage was associated with those twins where a very high Schmid factor was found on the slip systems parallel to the twin plane.
||Planned: Stand-alone book in which only your symposium’s papers would appear (indicate title in comments section below)