3D Characterization of Defect Gradients in the Near Surface Microstructures and BulkAlloys Via Polychromatic Microdiffraction
|Rozaliya I. Barabash 1,2, G E. Ice 1|
1. Oak Ridge National Laboratory (ORNL), One bethel Valley Road, Oak Ridge, TN 37932, United States
Unprecedented three-dimensional (3D) measurements of unpaired dislocation-density distributions are now possible due to an emerging class of instrumentation: the 3D x-ray crystal microscopes. These instruments use ultra-intense synchrotron x-ray sources and advanced x-ray optics to probe polycrystalline materials with submicron x-ray beams. By employing polychromatic x-ray beams and a virtual pinhole camera method, called differential aperture microscopy, 3D distributions of the local crystalline phase, orientation (texture) and elastic and plastic strain tensor distributions can be measured with submicron resolution in all directions. The elastic strain tensor elements can typically be determined with uncertainties less than 100 ppm. Orientations can be quantified to ~0.01 degrees and the local unpaired dislocation density can be simultaneously measured. Efforts are underway to improve the spatial resolution to less than 50 nm and to extend the technique to allow for measurements deep within materials. Because the 3D x-ray crystal microscope is a penetrating nondestructive tool, it is ideal for studies of mesoscale evolution of defects in materials. The unprecedented new information now coming from this new class of instrumentation will revolutionize our understanding the materials physics underpinning materials properties.
Presentation: Invited at E-MRS Fall Meeting 2007, Symposium J, by Rozaliya I. Barabash
See On-line Journal of E-MRS Fall Meeting 2007
Submitted: 2007-05-17 15:50 Revised: 2009-06-07 00:44
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