3D Determination of Grain Shape in FeAl by Focused Ion Beam (FIB) Tomography

Abstract Techniques for the 3D analysis of materials at the sub-micron level are of major importance for understanding the structure and performance of new nanoengineered materials. Established techniques for determining 3D shapes of individual grains include X-ray tomography and light microscopy for grains ≫ 1μm, and 3D-atom probe for conducting grains < 50nm size. A new technique of TEM EELS tomography is being developed for particles 2-300nm in a chemically distinct matrix. For the grain size range 200nm-20μm, we have applied a new technique of 3D analysis using focused ion beam (FIB) sectioning to the site-specific analysis of the shape of individual grains in a single phase matrix. in the 3D FIB technique, a sample surface may be serially sectioned using a highly focused beam of Ga+ ions (Fig. 1). A sequential set of 2D secondary electron images through the sample can be aligned in 3D by cross-correlation of the position of reference markers in the 2D images.