Abstract
Heading towards an increasing use of green hydrogen as a sustainable energy source, one of the current challenges is the absorption of hydrogen atoms into metallic components, leading to hydrogen embrittlement in many metals and alloys. For this instance, there is an increasing need for material testing in hydrogen conditions and the characterization of associated damage phenomena.
This study combines micro-computed tomography (µCT) as a three-dimensional non-destructive testing method with fracture mechanical experiments, scanning electron microscopy (SEM) and hydrogen uptake measurements, aiming to correlate the results for a more comprehensive understanding of hydrogen-induced damage mechanisms. A complete workflow for hydrogen charging, mechanical testing and multiscale characterization has been successfully developed—representing a novel approach for large compact tension specimens of low alloyed, ferritic steel and in particular for the integration of CT-based imaging. The hydrogen charging strategy has been optimized to maintain the promotor effect over the extended charging durations required for the sample geometry in this study. This was verified through inert gas fusion measurements, confirming hydrogen ingress in the material and the effectiveness of the promotor throughout the charging period. Mechanical testing further confirmed hydrogen presence during both crack initiation and subsequent crack growth. SEM fractography supported these findings, revealing distinct quasi cleavage facets, which are characteristic for hydrogen embrittlement. Initial µCT results indicated a trend toward smoother crack morphologies in hydrogen-charged samples, suggesting structural changes associated with hydrogen-assisted damage.