Under the Microscope: What Insight Can the Newest Tools yield about Radiation Effects in Materials?

10:00 AM - 11:00 AM
Chad M. Parish, Materials Science and Technology Division
Materials and Chemistry Seminar Series
Building 4500-N, Weinberg Auditorium
Email: Adrian Sabau

In the heyday of radiation-effects electron microscopy, roughly the 1960s to 1980s, tremendous insights into the evolution of metallic and ceramic materials under irradiation were gained, allowing the design and implementation of many new materials. However, as electron microscopy's spatial resolution and chemical sensitivities plateaued, and computer power advanced, theory approaches (i.e., molecular dynamics) have far outpaced microscopy in enabling recent advances in the understanding and deployment of materials for nuclear environments. This may be changing. In the last 5-10 years, revolutionary improvements in electron microscopy and atom probe tomography have become commercialized, allowing deep sub-nanometer imaging and single-atom chemical sensitivity. The simultaneous drive from traditional large-grained, microstructured materials to advanced fine-grained, nanostructured materials provides important problems that require new analytical techniques. Can microscopy begin to catch up with and validate theory? Can we begin gaining engineering insight from microscopy techniques that were recently laboratory curiosities? In this talk, I will discuss some recent ORNL work – nanostructured steels, silicon carbide, and MAX-phase ceramics – that use advanced atom probe tomography or aberration-corrected electron microscopy methods to try to solve difficult problems in radiation materials science that were previously unsolvable using the experimental characterization methods available even five or ten years ago. Research was sponsored by the Materials Sciences and Engineering Division, Office of Basic Energy Sciences, U.S. Department of Energy (work on nanostructured ferritic alloys), by the Office of Fusion Energy Sciences, U.S. Department of Energy (work on silicon carbide), and by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy (work on MAX-phase ceramics). Atom probe and microscopes accessed through a user project supported by ORNL’s Center for Nanophase Materials Sciences (CNMS), which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. A former Weinberg Fellow (2009-2011), Chad Parish is an R&D staff member at ORNL since 2012. His research interests are in the general area of microscopy of metals and ceramics for extreme environmental applications.


Coffee and cookies will be served.


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