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

XW Zhou and ME Foster and JA Ronevich and CW San Marchi, JOURNAL OF COMPUTATIONAL CHEMISTRY, 41, 1299-1309 (2020).

DOI: 10.1002/jcc.26176

Reducing hydrogen embrittlement in the low-cost Fe & x2500;C based steels have the potential to significantly impact the development of hydrogen energy technologies. Molecular dynamics studies of hydrogen interactions with Fe & x2500;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 & x2500;C & x2500;H ternary interatomic potential. In this work, the literature on interatomic potentials related to the Fe & x2500;C & x2500;H systems are reviewed with the aim of constructing an Fe & x2500;C & x2500;H potential from the published binary potentials. We found that Fe & x2500;C, Fe & x2500;H, and C & x2500;H bond order potentials exist and can be combined to construct an Fe & x2500;C & x2500;H ternary potential. Therefore, we constructed two such Fe & x2500;C & x2500;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 & x2500;C steels, including martensite that results from gamma to alpha phase transformation, and pearlite that results from the eutectic formation of the Fe3C cementite compound.

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