Shock Mitigation in Additively Manufactured 316L Stainless Steel with Controlled Porosity
ORAL
Abstract
Additive manufacturing (AM) of stainless steels facilitates tuning mechanical properties for unique functionalities, and stainless steel is a prime candidate for use in many applications due to its existing high strength, ductility, and corrosion resistance. AM fabricated stainless steel samples with randomly-placed pores are compared to those fabricated samples with no porosity at a variety of impact speeds to determine the effects of porosity on shock wave propagation and spall failure. Velocity profiles were obtained using photon doppler velocimetry (PDV), and samples were soft-recovered and analyzed post-shock using computerized tomography (CT) and electron backscatter diffraction to investigate void nucleation and coalescence in relation to pore locations. It is observed that the location of the pores in the spall plane affects shock wave propagation, up to and including spall mitigation. Spall failure is observed at a distance away from pores and in front of pores located further from the impact face. However, spall is not present behind pores placed towards the impact face, suggesting that the slowing of the shock waves through strain accommodation around the pores and pore collapse leads to spall mitigation. Further investigation of pores placed in known locations demonstrates shock wave mitigation near the pore even with the presence of a single pore.
*This research was supported in part by funding from the Steel Founders Society of America, Award No. AWD-002255. K.K. was supported by a NASA Space Technology Research Fellowship which also provided funding for the materials, supplies, and characterization performed in the present work. TS was supported by the Department of Energy through a cooperative agreement with the DOE NNSA Lab Residency Graduate Fellowship under contract DE-NA000396. KL was supported by Consolidated Nuclear Security, LLC (CNS) as accounts of work sponsored by an agency of the United States Government under Contract DE-NA-0001942. The characterization work was conducted at the Georgia Tech Institute for Electronics and Nanotechnology or Joint School of Nanoscience and Nanotechnology, a member of the National Nanotechnology Coordinated Infrastructure (NNCI), which is supported by the National Science Foundation (Grant ECCS-2025462).
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Publication:Koube, Katie, et al. "An Assessment of Spall Failure Modes in Laser Powder Bed Fusion Fabricated Stainless Steel 316L with Low-Volume Intentional Porosity." Journal of Applied Physics. Submitted for Publication, 2023
