|About this Abstract
|MS&T22: Materials Science & Technology
|Resisting Degradation from the Environment: A Symposium Honoring Carolyn M. Hansson’s Research and Pioneering Experiences as a Woman in STEM
|Investigation of Crack Initiation in Hydrogen Embrittled Ni-base Alloy 725
|Mengying Liu, Lai Jiang, Michael J Demkowicz
|On-Site Speaker (Planned)
The factors responsible for hydrogen embrittlement (HE) of metals remain imperfectly understood, with prevailing theories emphasizing H-induced decohesion or H-enhanced localized plasticity (HELP). We use in situ tensile testing to clarify the role of slip in the initiation of intergranular cracks in alloy 725. We quantitatively assess the HELP hypothesis using melt extraction to measure H content and digital image correlation (DIC) to analyze localized plastic strains during in situ tensile tests in a scanning electron microscope (SEM). We find localized slip is neither necessary nor sufficient for crack initiation. The role of slip is likely to reduce local cohesive strength and create local stress concentrations that promote decohesion. Understanding the mechanism can help with improving future alloy design and lifetime prediction.