Dislocation cells in additively manufactured metallic alloys characterized by electron backscatter diffraction pattern sharpness

• Published in: Materials characterization 2023-03, Vol.197, p.112673, Article 112673
• Main Authors: Wang, Fulin, Stinville, Jean-Charles, Charpagne, Marie, Echlin, McLean P., Agnew, Sean R., Pollock, Tresa M., Graef, Marc De, Gianola, Daniel S.
• Format: Article
• Language: English
• Subjects: Additive manufacturing; Dislocation cell; Electron backscattering diffraction (EBSD); Metal and alloys; Microstructure
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2023.112673

•Use EBSD pattern sharpness to characterize dislocation cells in AM metallic alloys.•EBSD pattern sharpness reveals variations in local dislocation density.•It is an orientation-insensitive metric for characterizing dislocation cells.•Enables correlated multi-modal characterization of dislocations on mesoscale.•The cell walls in SLM alloys do not always possess large fraction of GNDs. Metallic alloys produced by additive manufacturing often host complex and hierarchical microstructures with grains exhibiting large orientation gradients, along with sub-grain dislocation cells. These multiscale features act in concert to control mechanical behavior, yet are challenging to characterize at high fidelity over large areas. Here, we quantify the sharpness of electron backscatter diffraction patterns obtained from several additively manufactured metallic alloys to directly image the dislocation cells at the mesoscale in bulk materials. The sharpness metric employed herein reflects the elastic strain field from dislocations, and exhibits unique advantages, including being proportional to local dislocation density, insensitive to grain orientation, and inherently correlated with orientation mapping and its related modalities. Our results demonstrate that the cell walls do not always possess appreciable misorientations, and thus do not always contain large fractions of geometrically necessary dislocations, thereby furthering our understanding of the origin and implications of the profuse dislocation cells produced during additive manufacturing.