The transport, storage, and utilization of hydrogen in many industries requires metallic components, such as valves, tubing, sensors, and pressure vessels. The austenitic stainless steel 316L is a common choice for these components due to the negligible influence of hydrogen on the ductility and toughness of annealed 316L. However; some applications require components with complex geometries and/or materials with higher yield strengths, and in these cases additively manufactured 316L can be an excellent alternative to conventionally-manufactured 316L. Although significant research has been performed on the hydrogen embrittlement of conventionally-manufactured 316L, it is unknown to what extent additively-manufactured 316L is also embrittled by hydrogen.

In this study the influence of hydrogen on additively-manufactured and conventionally-manufactured 316L is evaluated through in situ mechancial testing performed in an autoclave pressurized with hydrogen gas. Engineering stress-strain curves from tensile tests of both materials performed in 10 MPa hydrogen gas are shown in Figure 1. Strain-controlled fatigue testing was also performed in 10 MPa hydrogen gas. Additionally, the 316L materials were pre-charged at three different temperatures to determine differences in hydrogen solubility of the additively- and conventionally- manufactured 316L and to assess the effect of internal hydrogen on these materials. Hydrogen embrittlement of these materials is compared based on the effect of hydrogen on the tensile properties, the cycles to failure during fatigue testing, and the fracture modes as determined through scanning electron microscopy.