A novel approach to index site-specific grain boundary plane

A novel approach using focused ion beam (FIB) and electron backscatter diffraction (EBSD) or transmission Kikuchi diffraction (TKD) was developed to characterize all five parameters of the individual grain boundary. With this approach, the grain orientations and the grain boundary trace angles on two perpendicular surfaces can be measured. Then the grain boundary plane normal in the sample coordinate system can be determined and transformed to plane indices in the two crystal coordinate systems. FIB-TKD is a viable alternative to FIB-EBSD when EBSD measurement can't be conducted on the sample surface which is degraded by oxidation or corrosion. This approach was verified on a coherent twin boundary in alloy 690. The accuracy of the present FIB-EBSD method is better than 3°. This approach provides a convenient and efficient solution for measuring all five parameters of a site-specific grain boundary during FIB sample preparation.