As part of a 2015 capital equipment investment, a Bruker Electron Backscatter Diffracton (EBSD) system has been installed on the Mira SEM in Bard Hall. EBSD is primarily a technique for obtaining grain orientation information from highly polished samples. It can also reveal the microstructure and, using advance software, can give strain information. The image on the left is a full EBSD scan over ~60 minutes of Austenite steel. An inverse pole figure color map is created which gives the crystallographic orientation of the grains with respect to the sample directions. The approximate minimum grain size that can be analyzed is 30 – 40 nanometers.
The EBSD detector also has three RGB electron forescatter detectors (FSD). The FSD allow for rapid, < 1 minute, survey of a sample prior to doing a long scan. For example, the image below is a forescatter image of the above Austenite steel map region.
The determination of individual grain orientation is done by analyzing the Kikuchi pattern generated by electron diffraction from the sample. The image at left is a Kikuchi pattern from an individual grain in the Austenite steel. For the optimal pattern quality samples should be polished to ~0.05 micron surface finish.
Contact Don Werder or Maura Weathers for more information.