In-situ neutron diffraction study on hydrogen embrittlement of 316L at cryogenic temperatures

There is a great need for further research to be carried out on hydrogen embrittlement at lower temperatures. At low temperatures the volumetric energy density can be significantly increased and one key drawback in the use of hydrogen as a net zero fuel source can be combatted. This becomes more complex when studying 316L steel which already deforms in different modes as the temperature decreases from room temperature. Many studies have declared that hydrogen will reduce the stacking fault energy (SFE) of 316L from observations of early onset of twinning, but a recent study challenged this using in situ neutron diffraction at room temperature and deduced that the early onset of twinning is due to a change in solid solution strengthening. I propose that in situ neutron diffraction tests during cryogenic deformation to be carried out on hydrogen charged specimens, analysing the changes in deformation as the temperature is reduced, when twinning deformation and strain induced martensite transformation becomes more prevalent due to the temperature-dependent SFE being reduced. By studying the hydrogen affects in the lower temperature range down to liquid hydrogen temperature, additional findings on how hydrogen embrittlement will affect 316L storage tanks when storing cryo-compressed or liquid hydrogen can also be made.