Experiments and simulation on hydrogen assisted fracture of Nickel-base superalloys
Akbar Bagri (MIT), John Hanson (MIT), Jonathan Lind (CMU), Robert Suter (CMU), Peter Kenesei (Argonne National Laboratory), Michael Demkowicz (), Silvija Gradecak ()
Engineering Mechanics and Materials in the Oilfield
Wed 10:45 - 12:15
CIT 227
Using high energy diffraction microscopy (HEDM)and X-ray absorption tomography (XRAT), we investigate crack morphologies in Nickel-base superalloys that had been fractured in a hydrogen (H) environment. Unlike other techniques, HEDM and XRAT are capable of characterizing cracks and GB networks nondestructively. Our analysis focuses on locating ligaments that bridge mating crack faces and determining the crystallographic character of such ligaments, especially the grain boundaries (GBs) found in them. We then construct corresponding atomic-scale models of these GBs and assess the effect of H on them. Our results elucidate the connection between the structure of GBs and their susceptibility to H-assisted fracture.