Effect of Hydrogen on Plasticity in Advanced High-Strength Steels Used in Automotive Applications

This work studied the influence of hydrogen trapped in retained austenite on the mechanical properties of advanced high strength steel (AHSS) in tensile testing. It was found that hydrogen affected both the true strain at necking as well as the true fracture strain, when compared to a non-charged specimen. Moreover, when testing specimens with varying amounts of retained austenite, the drop in true strain at necking was in correlation to the amount of retained austenite present in the AHSS, while no such correlation was present for true fracture strain. The results from this work indicate that while trapping of hydrogen is usually seen as a positive mitigating mechanism of hydrogen embrittlement, for steels with retained austenite it may severely limit the capability for strain hardening. This could have severe consequences, for example, for a shock-absorbing crash box component in an automotive.