First-principles study of the hydrogen absorption at Σ5 symmetrical tilt grain boundary in B2-TiFe alloy

We present a density functional theory (DFT) study of the hydrogen-metal interaction in the B2-TiFe alloy with Σ5(310) symmetrical tilt grain boundary (GB) and (310) free surface (FS). The influence of hydrogen on the electronic properties of alloy with GB and FS is analyzed for different hydrogen sorption sites. The hydrogen absorption/adsorption, binding and segregation energies are calculated at GB and FS. Our calculations reveal that H segregates more strongly to the surface than to the GB that results in decrease in the Griffith work, i.e., H makes the fracture of the GB easier.

► The H absorption is more preferable in the distorted Ti-rich octahedral interstice at GB.
► The adsorption energies indicate a strong H-metal interaction on surface.
► H adsorption is energetically more favorable on terrace sites than at step edges on TiFe(310).
► Calculated segregation energies show that H segregates more preferentially to surface than to GB.
► H segregation behavior results in decrease of the Griffith work and makes the fracture of GB easier.