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Hydrogen diffusion properties and hydrogen-induced ductility loss of an as-built 17-4PH stainless steel fabricated by the additive manufacturing (AM) process were investigated using hydrogen-charged specimens exposed to high-pressure gaseous hydrogen and the results were compared with those of a conventionally manufactured 17-4PH steel under solution-treated (ST) and precipitation-hardened (PH) conditions. Peak-aged (H900) and over-aged (H1150) steels were prepared for the PH conditions. The austenite fraction of the AM materials was at most three times higher than that of the ST material. Except for the H900 material, the saturated hydrogen content of both the AM and conventional materials was dominated by the austenite in the materials. Hydrogen trapping by Cu precipitation, not the austenite, was considered to be mainly responsible for the saturated hydrogen content of the H900 material. The hydrogen diffusivity for both the AM and ST materials also decreased with higher austenite fractions. In the uncharged situation, the reduction in area (RA) of the AM material was larger than that of the conventional materials. In the hydrogen-charged situation, the AM material had a lower relative reduction in area (RRA) compared to that of the ST material, although their tested tensile strengths were similar. The hydrogen-charged AM and ST materials had quasi-cleavage (QC) surfaces. Voids elongated in the direction perpendicular to the loading direction, which corresponded with the QC facets, were observed from the longitudinal cross sections of both the AM and ST materials, suggesting the contribution of hydrogen–dislocation interactions.

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• Creative Commons BY-NC-ND Attribution-NonCommercial-NoDerivs 4.0 International
  

Keyword: Hydrogen embrittlement, 17-4 PH steel, Additive manufacturing, Slow strain-rate tensile testing, Retained austenite

Date published: 2024-05-14

Publisher: Elsevier BV

Journal:

• Engineering Failure Analysis (ISSN: 13596454) vol. 162 108437

Funding:

Manuscript type: Author's version (Accepted manuscript)

MDR DOI: https://doi.org/10.48505/nims.5174

First published URL: https://doi.org/10.1016/j.engfailanal.2024.108437

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Updated at: 2024-12-17 15:58:49 +0900

Published on MDR: 2026-05-14 08:28:37 +0900