Plastic deformation and phase transformations in austenitic steels in the course of hydrogen charging and subsequent mechanical tests

This study aims to shed light on some uncertainty in the effect of hydrogen-induced ε-martensite on mechanical behavior of hydrogen charged austenitic steels. It is shown that cathodic charging of austenitic steels is accompanied by plastic deformation, which creates the crystallographic texture and decreases plasticity during subsequent tensile tests. This deformation is the main reason for the hydrogen-induced γ→ε transformation. The ε-martensite is formed in the hydrogen-rich areas of the austenite, which decreases the hydrogen content in the retained austenite. In case of a small fraction of the hydrogen-induced ε-martensite, it can be additionally formed during subsequent mechanical tests due to trip effect, which diminishes the hydrogen loss of plasticity.