This is a past event.

Materials Science and Engineering Seminar

Dr. Mary O’Brien

Los Alamos National Laboratory

Abstract

Hydrogen embrittlement (HE) is a long-standing challenge in metallurgy due to unpredictable failures observed in numerous metallic systems exposed to hydrogen containing environments. Ductility loss is attributed to any combination of the following: formation of brittle hydrides upon supersaturation, decohesion along boundaries due to trapped hydrogen, or hydrogen enhanced localized plasticity (HELP) due to soluble hydrogen. I spent 7 years of my life trying to understand how hydrogen can cause internal cracks to form in oil and gas pipelines, and what we can do to prevent it. I will discuss some of what that journey looked like for me, so that I can inform you why I would have gone on to LANL to propose investigating the effect of hydrogen on uranium. Uranium, with its low symmetry crystal structure, presents a unique opportunity to observe the proposed hydrogen-induced early-onset plasticity without added complications of slip system interactions that occur in most engineering materials. Electron backscatter diffraction has revealed that hydrogen charging reduces twin growth. These results will be discussed in the context of recent advanced characterization results alongside plans for future work. But this won’t be just another boring technical talk. It’s a talk about what it has looked like for me to evolve into a scientist and what it means to ask hard questions. I will give examples of failures and successes I have had along the way in hopes of showing that behind every CV is a story of ups and downs that scientists rarely ever talk about in public. I hope to show that anyone interested in questioning everything, regardless of past choices, can learn to be a scientist.

Bio

Mary O’Brien is a staff scientist on the Materials Compatibility Team, in Sigma Manufacturing Sciences Division at LANL. Her research focus is understanding hydrogen embrittlement phenomena in a wide variety of metallic systems, with a current focus on actinide materials. Mary earned a BS in Materials Science and Engineering from Washington State University, and MS and PhD in Metallurgical and Materials Engineering from Colorado School of Mines. Her graduate research involved understanding hydrogen induced cracking in low carbon pipeline steels for oil and gas applications. Prior to attending graduate school, she worked as a civilian nuclear engineer at Puget Sound Naval Shipyard refueling Ohio class submarines. Mary spends her free time exploring New Mexico on bikes, skis, and sometimes skates with her partner and her corgi Jesse. She is passionate about volunteering to enhance diversity both in STEM and in the outdoors and has taken on several roles both locally and nationally towards this goal.