Sun, F.; Adachi, Y.; Sato, K.; Ishimoto, T.; Nakano, T.; Koizumi, Y. Delineating the Ultra-Low Misorientation between the Dislocation Cellular Structures in Additively Manufactured 316L Stainless Steel. Materials2024, 17, 1851.
Sun, F.; Adachi, Y.; Sato, K.; Ishimoto, T.; Nakano, T.; Koizumi, Y. Delineating the Ultra-Low Misorientation between the Dislocation Cellular Structures in Additively Manufactured 316L Stainless Steel. Materials 2024, 17, 1851.
Sun, F.; Adachi, Y.; Sato, K.; Ishimoto, T.; Nakano, T.; Koizumi, Y. Delineating the Ultra-Low Misorientation between the Dislocation Cellular Structures in Additively Manufactured 316L Stainless Steel. Materials2024, 17, 1851.
Sun, F.; Adachi, Y.; Sato, K.; Ishimoto, T.; Nakano, T.; Koizumi, Y. Delineating the Ultra-Low Misorientation between the Dislocation Cellular Structures in Additively Manufactured 316L Stainless Steel. Materials 2024, 17, 1851.
Abstract
Sub-micro dislocation cellular structures formed during rapid solidification break the strength-ductility trade-off in laser powder bed fusion (LPBF)-processed 316L stainless steel through high-density dislocations and segregated elements or precipitates at the cellular boundaries. The high-density dislocation entangled at the cellular boundary accommodates solidification strains among the cellular structures and cooling stresses through elastoplastic deformation. Columnar grains with cellular structures typically form along the direction of thermal flux. However, the ultra-low misorientations between the adjacent cellular structures and their interactions with the cellular boundary formation remain unclear. In this study, we revealed the ultra-low misorientations between the cellular structures in LPBF-processed 316L stainless steel using conventional electron backscatter diffraction (EBSD), transmission Kikuchi diffraction (TKD), and transmission electron microscopy (TEM). The conventional EBSD and TKD analysis results could provide the misorientation angles smaller than 2° while the resolution mainly depends on the specimen quality and scanning step size, and so on. TEM technique with higher spatial resolution provides accurate information between adjacent dislocation cells with misorientation angles smaller than 1°. This study presents that TEM method is the better and more precise analysis method of the misorientation measurement of the cellular structures and provides insights into measuring the small misorientation angles between adjacent dislocation cells and nanograins in nanostructured-metals and alloys with ultrafine-grained microstructures.
Keywords
additive manufacturing; cellular structure; misorientation; transmission electron microscopy; transmission Kikuchi diffraction; electron backscatter diffraction
Subject
Engineering, Metallurgy and Metallurgical Engineering
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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