The resistance of stainless steels to shear localization is dependent on processing and microstructure. The amount of research evaluating the shear response of additively manufactured (AM) stainless steels compared to traditionally manufactured ones is limited. To address this gap, experiments were performed on directed energy deposition AM as-built and wrought 316L stainless steel using a forced shear technique with a hat-shaped specimen and a Split-Hopkinson pressure bar. The resulting adiabatic shear bands were characterized with electron backscatter diffraction (EBSD) and nanoindentation to quantify the changes in microstructure and deformation hardening across shear band regions and between the wrought and AM materials. Despite significant differences between the wrought and AM materials including the forced shear response, the postmortem states of work hardening due to the shear band deformation are nearly the same. The maximum nanoindentation stresses occurred in the shear band center with similar magnitudes and only minor differences away from the shear band. Although EBSD data cannot be resolved in the shear band center, misorientation trends, particularly grain reference orientation deviation, were found to closely resemble nanoindentation trends. The combination of EBSD misorientation and nanoindentation, which are linked through changes in dislocation density, is a viable protocol to quantify local changes to macroscopically applied deformation.
Bibliographical noteFunding Information:
The authors acknowledge funding from Joint Munitions Program. This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the US Department of Energy (DOE) Office of Science. The Los Alamos National Laboratory, an affirmative action equal opportunity employer, is operated by Triad National Security, LLC, for the National Nuclear Security Administration of the US Department of Energy under Contract #89233218CNA000001.
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