ChEMS Seminar: Precipitation in Fe-Cr Alloys under Irradiation

McDonnell Douglas Engineering Auditorium (MDEA)
Emmanuelle A. Marquis

Department of Materials Science and Engineering
University of Michigan, Ann Arbor, MI

Abstract: After a brief overview of our recent and current activities to understand the interplay between microstructures evolution, thermal exposure, irradiation, corrosion and oxidation, I will highlight our recent work on the effects of irradiation on precipitation in Fe-Cr alloys, a model system for widely used ferritic martensitic steels. In these alloys, nanoscale Cr-rich precipitates are expected to form under thermal annealing or low-dose-rate neutron irradiation. I will show that phase decomposition is strongly affected by cascade ballistic mixing, and ion irradiation at high irradiation dose rate leads to non-equilibrium Cr clustering that differ from those observed under neutron irradiation. These findings highlight one of the challenges in using ions and protons as surrogates for neutrons to understand, simulate or predict the evolution of microstructures for materials in realistic nuclear environments. 

Bio: Marquis is an associate professor in materials science and engineering at the University of Michigan. She is also the director of the Michigan Center for Materials Characterization, a campuswide shared facility.  She led the center re-organization to facilitate user access, successfully improved training and instrument maintenance, and modernized and brought new instrumentation. Prior to joining Michigan in 2011, Marquis obtained her Ph.D. from Northwestern University, was a postdoc and staff member at Sandia National Laboratory and a Royal Society Dorothy Hodgkin fellow at Oxford University. Her research interests focus on understanding alloy microstructure evolution as a result of external stimuli with an emphasis on using and developing characterization techniques. The latest activities of her research group can be found at https://marquislab.engin.umich.edu/

Host: Daniel Mumm