Hydrogen-enhanced deformation twinning in Fe-Cr-Ni-based austenitic steel characterized by in-situ EBSD observation

Direct evidence of solute hydrogen-assisted deformation twinning in Fe-24Cr-19Ni-based austenitic steel was acquired via an in-situ tensile test in a scanning electron microscope (SEM) equipped with electron backscattered diffraction (EBSD). Earlier activation of twinning on both primary and secondary systems by hydrogen was successfully visualized, in addition to recognizing an accelerated thickening of the existing twins. These alterations in twinning behavior were linked to an increase in the work-hardening rate at the later deformation stage, which is believed to be a root cause of recently discovered anomalous ductility improvement in the steels under the presence of solute hydrogen.

Automated summary

Direct evidence of solute hydrogen-assisted deformation twinning in Fe-24Cr-19Ni-based austenitic steel was obtained through an in-situ tensile test using a scanning electron microscope (SEM) equipped with electron backscattered diffraction (EBSD). Activation of twinning by hydrogen occurred earlier on both primary and secondary systems, leading to increased thickening of existing twins. These changes in twinning behavior were found to be associated with an accelerated work-hardening rate at later deformation stages, which is believed to be the underlying cause of the recently observed anomalous ductility improvement in steels with solute hydrogen.