New molecular dynamics studies of hydrogen effects on cross-slip energy barriers in austenitic stainless steels

XW Zhou and FD Leon-Cazares and C San Marchi, COMPUTATIONAL MATERIALS SCIENCE, 257, 113990 (2025).

DOI: 10.1016/j.commatsci.2025.113990

A new molecular dynamics method has been developed to calculate cross- slip constriction energy barrier based on energy as a function of constriction spacing. This method produces overall consistent results with methods previously applied in literature. Unlike the literature methods, however, our method can be easily extended to alloys containing mobile hydrogen. Application of our method to the Fe0.70Ni0.11Cr0.19 alloy with and without hydrogen indicates that the constriction energy barrier is around 1.7 - 2.0 eV without hydrogen, whereas this energy barrier significantly increases to 3.5 and 4.2 eV, with the addition of 0.5 % and 1.0 % (atomic) hydrogen. Comparison with linear elasticity theories reveal insights on the process of Shockley partial recombination and the role of hydrogen in the cross-slip process. Our results accounts well for the experimental observations of hydrogen induced planar slip localization. The new method, thereby, provides a powerful means to explore hydrogen embrittlement in future atomistic studies.

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