Speaker
Description
Hydrogen as the lightest element and the smallest atom in the periodic table tends to diffuse fast with the capability to re-distribute quickly and penetrate almost all materials. Understanding the interactions of hydrogen with host materials is of great interest for many applications, from hydrogen storage and green energy applications to hydrogen embrittlement. We use atom probe tomography (APT) to characterize atomic-scale distributions of hydrogen in an additively manufactured martensitic stainless steel. Hydrogen is essentially ubiquitous, including sample and equipment surfaces, and thus likely to cause a significant background signal in APT, we use isotopic labeling with deuterium (D) introduced via electrochemical charging to permit more detailed tracking of D and H in our samples. The local concentrations of H and D in the APT reconstructions are correlated with microstructural features present in this stainless steel, such as carbide precipitates and martensitic lath boundaries. We critically discuss the amounts and distributions of H and D detected to elucidate their potential trapping at these microstructural features and imperfections.
