SPring-8, the large synchrotron radiation facility

Date: 14:00-15:00   28th September (Tue.), 2010

Place: Kamitsubo Hall

Speaker: Robert M. Suter

Language: English

Affiliate: Department of Physics and Materials Science and Engineering, Carnegie Mellon University

Title: Non-destructive Mapping of Bulk Microstructures using High Energy X-ray Diffraction Microscopy

Abstract:
High energy (> 50keV) x-rays penetrate through millimeter sized samples and thus offer the opportunity to probe bulk structures and their responses to processing treatments. The 1-ID beamline at the Advanced Photon Source is a dedicated facility for high energy x-ray scattering offering a high energy undulator, focusing optics, a variety of two dimensional detectors and multiple sample environments. High Energy X-ray Diffraction Microscopy (HEDM) measurements focus on obtaining single crystal-like information from individual grains within bulk, polycrystalline ensembles. This talk will report primarily on near-field orientation mapping measurements but will also briefly illustrate some of the far-field capabilities at the beamline.

HEDM microstructure mapping measurements use a line focused x-ray beam to illuminate a quasi-planar cross-section of sample. Details of data collection protocols and our real-space microstructure reconstruction method will be presented. By collecting a sequence of planar sections we build three dimensional digital representations of microstructure similar to those obtained by 3D electron backscatter diffraction measurements. Because the HEDM measurement is non-destructive, we can track microstructural responses to thermal and mechanical treatments. These measurements are an ideal way to test and validate analytic and computational models of materials response. Measurements on a variety of elemental metals will illustrate experimental resolution in orientation and real space and the extent of development of analysis tools.

With a large far-field detector, strain states of individual grains become accessible. Work on a β-Ti alloy sample illustrates a close interplay between computational modeling of plastic response and direct measurements. Finally, the prospect of combining near- and far-field measurements to obtain full three dimensional maps of both crystallographic orientation and strain will be discussed.

Organizer: Kentaro Uesugi
PHS: 3928
uesugi@spring8.or.jp