X-Ray Diffraction Contrast Tomography for Probing Hydrogen Embrittlement in Heat-Treated Lean Duplex Stainless Steel

Laboratory-based diffraction contrast tomography (DCT) was applied to heat-treated lean duplex stainless steel (DSS) to observe microstructural changes by hydrogen infusion treatment. The feasibility of the DCT technique for the in situ assessment of a dual-phase material with exposure to aqueous solution was investigated, with DCT observations carried out before and after cathodic hydrogen charging. The movement of diffraction spots was observed after charging for 7 days, which cannot be explained by sample lateral movements. An experimental method to apply the DCT techniques for investigating the hydrogen–microstructure interaction is introduced here, but a more accurate experimental methodology is required to verify that the movement of diffraction spot derives from lattice parameter changes.