AME Department Seminar

Speaker: Mukul Kumar , Staff Scientist. Physical & Life Sciences Directorate. Lawrence Livermore National Laboratory. Livermore, CA 94550.

Talk Title: Grain Boundary Networks: From Consideration of the Individual Constituents to the Collective Response

Abstract: It has been demonstrated that mechanical response, particularly environmental degradation, of FCC metals and alloys can be improved by exercising control over the population of grain boundary types in the microstructure. The studies also suggest that such properties tend to have percolative mechanisms that depend on the topology of the grain boundary network. Grain boundary engineering investigations have been facilitated by the emergence of SEM-based automated electron backscatter diffraction (EBSD) that enables the characterization of statistically significant datasets of interface crystallography. The EBSD datasets have been analyzed to quantify microstructures in terms of grain boundary character and triple junction distributions. Perhaps more significantly, these large datasets also enable us to visualize crystallographically correlated domains of multiple grains that have been shown to strongly influence crack propagation through the microstructure. Examples from studies on hydrogen and weld embrittlement, stress corrosion cracking, and fatigue will be presented to demonstrate these points along with the constitutive response of such microstructures.

This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.



Biography: Mukul Kumar is a Staff Scientist in the Physical & Life Sciences Directorate at LLNL. Prior to joining LLNL, he received his PhD from the University of Cincinnati and had a stint as a postdoctoral fellow at Johns Hopkins University. His research activities have revolved around correlating microstructures with the macroscopic response of the material. This has involved diverse conditions such as travelling strong shock waves to challenging environments seen in jet engines and nuclear reactors. There is growing involvement in taking the next step of formulating predictive models for materials behavior, particularly damage and fracture, and translating them into processing routes for optimized microstructures.

Host: Prof. Andrea Hodge

More Info: http://ae-www.usc.edu/seminars/index.shtml#upcoming

Location: Seaver Science Library (SSL) - 150

Audiences: Everyone Is Invited

Contact: April Mundy

Event Link: http://ae-www.usc.edu/seminars/index.shtml#upcoming