Helium bubble nucleation in Laser Powder Bed Fusion processed 304L stainless steel

Juan Hou, Binbin Dai, Ying Li, Jianguang Zhao, Zhuoer Chen, Dong Pan, Yuman Zhu, Kai Zhang, Aijun Huang

Research output: Contribution to journalArticleResearchpeer-review

Abstract

The interest in application of Additive Manufacturing (AM) to nuclear industry stems not only from the benefits of design freedom and shortened lead time, but also from the possibility of enhancing the performance through microstructure control. One of the most important requirements for in-core structural material in nuclear power plants is helium resistance. The Laser Powder Bed Fusion (LPBF) processed 304L stainless steel possesses strong defect sinks such as high densities of dislocation-surrounded sub-grains and dispersed nano-inclusions. In this work the LPBF processed 304L in as-built and solution-annealed conditions along with a conventionally rolled counterpart were implanted with 350 keV He+ ion at 300 °C to 0.24 dpa (displacement per atom). Transmission Electron Microscopy (TEM) observations indicate significantly higher helium resistance of the as-built LPBF 304L compared to the other two samples. The sink strengths in the three samples are calculated based on the measurements of the microstructural features using simplified equations for the correlation between microstructural characteristics and helium tolerance. Based on the calculation, the cellular sub-grains and the dispersed nano-inclusions are the primary and secondary contributors to the helium resistance of LPBF 304L steel.

Original languageEnglish
Article number152443
Number of pages10
JournalJournal of Nuclear Materials
Volume542
DOIs
Publication statusPublished - 15 Dec 2020

Keywords

  • Helium bubble nucleation
  • Irradiation tolerance
  • Laser Powder Bed Fusion
  • Stainless steel
  • Thermal stability

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