HYDROGEN TRAPPING MECHANISMS- EXPERIMENTAL AND THEORETICAL MODELLING

Mechanical properties of metals and alloys are most often determined by interstitial atoms. Hydrogen, as one common interstitial element, is often found to degrade the fracture behavior and lead to premature or catastrophic failure in a wide range of materials, known as hydrogen embrittlement. This topic has been studied for more than a century, yet the basic mechanisms of such degradation remain in dispute for many metallic systems. This work attempts to link, experimentally and theoretically, between failure, caused by the presence of hydrogen, and second phases, lattice distortion, and deformation levels.

The connection between hydrogen embrittlement and pathway is established through examination of the evolved microstructural state by hydrogen. Analytical modeling for statistical cracking and hydrogen trapping states in the case of low and high loading was applied. Calculations performed by thermal desorption analysis showed the effectiveness of high trapping energy levels in preventing the hydrogen embrittlement phenomena. It was proved that the embrittlement model is highly affected by the trapping mechanisms. These results were confirmed by a diffusion calculation model and a theoretical model that predicts hydrogen trapping mechanisms.