Hydrogen diffusion and trapping in a cryogenic processed high-Cr ferrous alloy

The effect of hydrogen diffusion and trapping was studied in a high-Cr ferrous alloy using an inverted scanning Kelvin probe and thermal desorption spectroscopy in correlation with microstructure and residual stress study. In addition, different processing of ferritic/martensitic 9Cr1WTaV alloy (EUROFER97) was tested in correlation with observed selected properties to observe induced changes in material degradation and surface. The activation energies for hydrogen traps were shown to have distinct peaks corresponding to different trapping mechanisms, including matrix dislocations and grain boundaries. For the cryogenically treated sample, an additional peak was also identified and correlated with increased carbide precipitation.