|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Fatigue in Materials: Fundamentals, Multiscale Modeling and Prevention
||Investigation of Nonmetallic Inclusion-driven Failures
||Diwakar Naragani, Michael Sangid, Paul Shade, Jay Schuren, Hemant Sharma, Jun-Sang Park, Peter Kenesei, Joel Bernier, Todd Turner
|On-Site Speaker (Planned)
Crack initiation at inclusions is a dominant and unavoidable failure mechanism as fatigue progresses to find the ‘weakest link’ in the material to nucleate a crack. It is critical to identify a microstructurally informed driving force to characterize this failure mode. An experiment was conducted on a Ni-based superalloy sample with a seeded non-metallic inclusion under cyclic loading. The test was sequentially interrupted to conduct absorption contrast tomography to determine spatial and morphological information about the inclusion. Far field high energy x-ray diffraction microscopy was carried out to simultaneously characterize the microstructure. The centroid position, average orientation and stress state of the grains have been determined intermittently until crack initiation. The reconstructions elucidate temporal and spatial strain evolution of grains especially around the initiation site. Strain heterogeneity and the associated stress localization containing crucial information regarding damage evolution and accumulation are employed to determine the driving force for crack initiation.
||Planned: Publication Outside of TMS (Indicate publication title and publisher if known.)