A large-volume 3D EBSD study on additively manufactured 316L stainless steel

Most microstructure characterization tools are based on the observation of two-dimensional (2D) sections through a material. The results allow, for microstructures with homogeneous and often equiaxed grain shapes, a sufficiently good interpretation of microstructure formation and materials properties. Such microstructures are typically recrystallized grains or homogeneously deformed grains in plastically deformed materials. In contrast, metal parts fabricated by additive manufacturing (AM) exhibit microstructures that differ significantly from classical materials as they frequently develop very heterogeneous and often nonregular grain structures. Orientation microscopy-based electron backscatter diffraction (EBSD) is probably the most quantitative materialographic technique for 2D microstructure characterization. By combination with serial sectioning the technique is extended to a powerful 3D characterization technique. Here we use a large-volume 3D EBSD system (ELAVO 3D) to analyze an AM-built 316L stainless steel sample. The results show unique "tree-like" grain morphologies and related textures. We highlight issues invisible when using 2D EBSD.