First-Principles study of hydrogen solubility and embrittlement of Cr23C6 in nickel-based alloys

This research examines the crucial role played by Cr23C6 23 C 6 carbides in hydrogen trapping and their subsequent impact on the mechanical properties of the material. The hydrogen solution energies at different defect sites within the bulk phase of Cr23C6 23 C 6 and the Ni/Cr23C6 23 C 6 interface were analyzed using first-principles computations. This study underscores the notable vulnerability of nickel-based alloys to hydrogen embrittlement as the carbide content increases. Substantial hydrogen enrichment at the Ni/Cr23C6 23 C 6 interface, particularly at octahedral interstitial sites on the Ni side and C vacancies at the interface, was identified through comprehensive atomistic simulations. This enrichment negatively affects separation at the interface, indicating an increased risk of brittle fracture in the presence of hydrogen. By providing insights into the microscopic processes involved, our results seek to contribute to the development of nickel-based alloys that are more resistant to hydrogen, thereby influencing material selection and treatment in industrial applications prone to hydrogen embrittlement.