Under the Microscope: What Insight can the Newest Analytical Tools Yield About Radiation Effects in Materials?

Chad M. Parish, Oak Ridge National Laboratory

Thursday September 24, 2015, 11:00 a.m. – 12:00 p.m

EBUII, Room 479

ABSTRACT: 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, radiation-resistant ceramics, and fusion plasma-facing materials – that used advanced 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.

BIO: Dr. Chad Parish joined ORNL in 2009 as an Alvin M. Weinberg fellow. He previously was a post-doctoral scholar at Sandia National Laboratories (2007-2009) and completed a Ph.D. at North Carolina State University in 2006. In 2011, Chad finished his Weinberg Fellowship and continued as a staff research scientist. Chad's current research involves solving problems in materials for extreme environments, emphasizing the methods of microscopy and microstructural characterization. Chad received an Office of Science Early Career Research Program award from the Office of Fusion Energy Sciences in 2015. His current research involves irradiation effects in fusion plasma-facing materials, advanced steels, and advanced ceramics.