Simulation study on mechanical properties of nanocrystalline Fe with hydrogen atom segregated on grain boundaries

Abstract Molecular dynamics simulation method has been adopted to scrutinize the reactions of hydrogen atom segregation within the grain boundary affect zones of a polycrystalline Fe model. The primary focus is to discern the influence of varied hydrogen concentrations on the failure behaviors exhibited during plastic deformation. The investigation aims to straighten out the mechanical characteristics and failure mechanisms at the microscale in polycrystalline iron. Moreover, the study monitors and analyzes alterations in the crystal structure of the polycrystalline iron model under tensile loading, employing the common neighbor analysis technique. Findings indicate that tensile strength, Young's modulus, and strain when reaching the tensile strength diminish as hydrogen concentration increases, thereby heightening the propensity for failure in polycrystalline iron. In stress conditions, the congregation of hydrogen atoms tends to facilitate dislocation, void formation, and precipitate brittle fractures. The insights garnered from this investigation not only enhance our comprehension of micro-failure mechanisms in hydrogen-affected infrastructures but also furnish essential theoretical support for ensuring the reliability and safety of hydrogen transmission pipelines.