Characterization of in-situ and ex-situ Ion-Irradiated Additively Manufactured 316L and 316H Stainless Steels

Journal Article · Wed Aug 06 00:00:00 EDT 2025 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2025.156044· OSTI ID:3013592

Chen, Wei-Ying ^[1]; Taller, Stephen ^[2]; Jokisaari, Andrea M. ^[3]; Chen, Yiren ^[1]; Song, Rongjie ^[3]; Gao, Lin ^[1]; Baldo, Peter M. ^[1]; Habaruk, Dzmitry ^[1]; Li, Meimei ^[1]

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1. Argonne National Laboratory
2. Oak Ridge National Laboratory
3. Idaho National Laboratory

Additively manufactured (AM) 316 stainless steel (SS) differs from its wrought counterpart in its unique dislocation cell structure and the presence of segregation and oxide particles at the cell walls. This work investigated the evolution of the microstructure in laser powder bed fusion (LPBF) 316L and 316H SS under in-situ 1 MeV Kr ion irradiation at 600°C to 5 dpa, and ex-situ 4 MeV Ni ion irradiation at 300°C and 600°C from 0.2 dpa to 10 dpa, with a dose rate for all experiments of 10-3 dpa/s. The results reveal that the dislocation cell structure result in heterogeneous formation of dislocation loops and voids, particularly at 600°C, where loops tend to form within the cell interiors while voids form at the cell boundaries. LPBF 316H has a reduced level of swelling compared to LPBF 316L due to prolonged incubation. Energy Dispersive X-ray Spectroscopy (EDS) mapping indicates Ni and Si segregation at void surfaces due to radiation-induced segregation. At 300°C, where voids are absent, the distribution of dislocation loops and stacking fault tetrahedra appears to be uniform. Dislocation cell structures mostly disappeared by 2 dpa for all conditions in this work. M23C6 carbides were observed in LPBF 316H at 600°C as early as 0.2 dpa, but not in LPBF 316L. Nanoindentation was performed to obtain the hardness of irradiated materials. This work illustrated the influence of additive manufacturing processes on microstructure evolution under irradiation, revealing the differences as well as the similarities as compared with wrought 316 SS, and the AM-related phenomenon that can potentially occur under neutron irradiation in nuclear reactors.

• Research Organization: Idaho National Laboratory (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• Grant/Contract Number: AC07-05ID14517
• OSTI ID: 3013592
• Report Number(s): INL/JOU-25-86993
• Journal Information: Journal of Nuclear Materials, Journal Name: Journal of Nuclear Materials Journal Issue: October, 2025 Vol. 616
• Country of Publication: United States
• Language: English

Related Subjects

Dislocation Loops
Irradiation Effects
Stainless Steel
Voids
36 - MATERIALS SCIENCE
Additive Manufacturing