Abstract
Hydrogen embrittlement has posed a significant engineering challenge for many decades. Despite extensive research, the underlying mechanisms, optimal testing/modelling approaches, and effective mitigation strategies remain subjects of ongoing debate. Most studies have focused on the complex interactions between hydrogen and the metals' crystal structures, including lattice defects, local stress and plastic strain states. However, a critical aspect remains insufficiently understood: predicting the amount of hydrogen that enters metals. Since hydrogen absorption is the initial step in the embrittlement process, advancing our understanding of how metals absorb hydrogen under various environmental conditions is essential, from fundamental mechanisms to practical engineering applications. This paper provides a brief overview of hydrogen absorption pathways and highlights the potential and limitations of some current experimental techniques used to address this challenge.