Direct observation of hydrogen-trapping sites in newly developed high-strength mooring chain steel by atom probe tomography

Hydrogen-trapping sites were directly observed by using a three-dimensional atom probe (3DAP) in high-strength mooring chain steel. Three typical 3DAP datasets show that trapping hydrogen is mainly enriched in retained austenite, and secondarily in carbides. In addition, these interfaces between ferrite and carbide are segregated by phosphorus, but do not admit hydrogen.