Abstract
This work evaluates the possibilities of 3D electron backscatter diffraction (EBSD) to investigate hydrogen induced cracks in different materials. Hydrogen induced cracks were introduced by electrochemical hydrogen charging in three strongly differing materials, i.e. ULC (Ultra Low Carbon) steel, TRIP (TRansformation Induced Plasticity) steels and carbide containing materials. Such materials were selected in order to demonstrate the capabilities of the technique under investigation. EBSD measurements allow a complete microstructural and crystallographic characterization of hydrogen induced crack surroundings. In order to characterize the cracks in their full 3D nature, focused ion beam (FIB) serial sectioning in combination with electron backscatter diffraction (EBSD) was carried out. The effect of hydrogen on crack initiation and propagation, and more specifically the role of hydrogen interaction with varying microstructural features, e.g. grain boundaries, phases, dislocations, etc., on crack initiation and propagation can be explored. Additionally, strain fields surrounding cracks can be visualized, which for instance can help interpret crack tip interaction or evaluate proposed hydrogen theories (e.g. HELP). A deeper understanding on the mechanism(s) governing hydrogen induced crack initiation and propagation can as such be obtained. The results showed the valor of the 3D EBSD technique in the study of hydrogen induced crack study in varying microstructural circumstances.