A comparison study of void swelling in additively manufactured and cold-worked 316L stainless steels under ion irradiation

We studied the void swelling in stress-relieved (SR) additively manufactured (AM) 316L stainless steel (SS) in comparison with hot-isostatic pressed (HIP) AM 316L counterparts with identical chemistry. To understand the role of dislocation cell structure in SR AM 316L SS, we also included cold-worked (CW) 316L SS with various CW levels for dislocation networks. The irradiation damage of 30 displacements per atom (dpa) in AM and CW 316L SSs were compared after 5 MeV Fe2+ ion irradiations at 500 degrees C, 550 degrees C, and 600 degrees C, respectively. To investigate the temperature and dose dependence, the AM 316L SSs were further irradiated to 100 dpa at 400 degrees C and 600 degrees C. Results show that the void welling in SR AM 316L SS is more severe than in HIP AM 316L SS, in terms of a higher void density and a deeper void nucleation depth through all the examined conditions. This is ascribed to a more extended incubation period in HIP AM 316L SS. Beyond the incubation, both samples proceeded at a similar swelling rate. Dislocation networks from cold-working can effectively suppress void swelling, while dislocation cell structures containing entangled dislocations on cell walls cannot. The distinct responses indicate the potential influence of dislocation configuration on void swelling. Despite some relevant data are available, our understandings of radiation damage in AM 316L SSs are still limited. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The void swelling in stress-relieved additively manufactured 316L stainless steel was found to be more severe than that in hot-isostatic pressed counterparts, attributed to a longer incubation period. Dislocation networks from cold-working can effectively suppress void swelling, while dislocation cell structures cannot.