Review and construction of interatomic potentials for molecular dynamics studies of hydrogen embrittlement in Fe─C based steels

Abstract

Reducing hydrogen embrittlement in the low‐cost Fe─C based steels have the potential to significantly impact the development of hydrogen energy technologies. Molecular dynamics studies of hydrogen interactions with Fe─C steels provide fundamental information about the behavior of hydrogen at microstructural length scales, although such studies have not been performed due to the lack of an Fe─C─H ternary interatomic potential. In this work, the literature on interatomic potentials related to the Fe─C─H systems are reviewed with the aim of constructing an Fe─C─H potential from the published binary potentials. We found that Fe─C, Fe─H, and C─H bond order potentials exist and can be combined to construct an Fe─C─H ternary potential. Therefore, we constructed two such Fe─C─H potentials and demonstrate that these ternary potentials can reasonably capture hydrogen effects on deformation characteristics and deformation mechanisms for a variety of microstructural variations of the Fe─C steels, including martensite that results from γ to α phase transformation, and pearlite that results from the eutectic formation of the Fe3C cementite compound.

Design of advanced steels by integrated computational materials engineering

“…Hydrogen:By means of DFT, study the hydrogen adsorption and diffusion on the surface of alloyed steel [46] ; or the electronic and diffusion properties of hydrogen isotopes in 2.25Cr1Mo steel [47] ; or the effect of hydrogen in austenitic stainless steels and high entropy alloys [48] ; or hydrogen embrittlement of 12Cr2Mo1R (H) steel [49] [50] ; review and construct interatomic potentials for MD studies of hydrogen embrittlement in Fe‐C based steels [51] Phase transformation:By means of MD, simulate the fcc‐to‐bcc transformation in pure iron and summarize the affecting factors on the mechanisms [52] ; study the interface dynamics during the α ↔ γ transformation [53] ; simulate the α ↔ γ phase transition in Fe–C [54] …”

“…By means of MD, study the interactions of hydrogen with the iron and iron carbide interfaces [50] ; review and construct interatomic potentials for MD studies of hydrogen embrittlement in Fe‐C based steels [51] …”

An interplay between a hydrogen atmosphere and dislocation characteristics in BCC Fe from time-averaged molecular dynamics

“…The Fe–C–H bond-order potential 24 was used to simulate our systems. The elastic parameters of this potential agree with DFT simulations and experiment.…”

Molecular dynamics based study on the effect of hydrogen on the mechanical properties of Fe-C system

“…As a final step, a strain rate equal to 6.7 x 10 8 s -1 is applied in the longitudinal axis of the box (Y-axis) for a duration of 1.5 ns, which results in a total strain of 1.005. The interatomic potential file used for these simulations is a ternary Fe-C-H Bond Order Potential (BOP), specifically the BOP I, developed by Zhou et al [24], at Sandia National Laboratories. This ternary potential was created from combining existing Fe-C, Fe-H and C-H BOPs and was demonstrated, by the creators, to reasonably capture the effect of H on deformation characteristics and mechanisms for a variety of microstructural variations of Fe-C steels.…”