Graphene induced transition from pile-up to sink-in and its influence to contact damage on Fe(110) during nanoindentation

X He and XB Zhuo and QS Bai and JX Bai and GF Ding and L Jiang, SURFACES AND INTERFACES, 72, 107231 (2025).

DOI: 10.1016/j.surfin.2025.107231

Due to the strong chemical bonding between iron and graphene, graphene coatings exhibit exceptional protective properties for iron substrates. However, research on the underlying protective mechanisms remains insufficient. In this study, we present findings obtained from molecular dynamics simulations, revealing that graphene coatings can lead to a complete transformation of the indentation morphology in single-crystal iron from pile-up to sink-in that has not been reported. This remarkable alteration is particularly noteworthy, especially considering that graphene is only one atom thick. To this end, we firstly analyzed the formation mechanism of pile-up in Fe(110) plane. Subsequently, we integrated the characteristics of the atomic potential energy field and the dislocation network within the substrate to elucidate the restrictive effect of graphene coating on dislocation movement, which can lead to a more uniform strain field and an increased storage of elastic energy. The characteristics of the plastic zone surrounding the indentation were examined from multiple perspectives, including the spatial distribution of defects, the types and lengths of dislocation lines, among others. Further investigations indicate that graphene can reduce the size of the plastic zone and promote the formation of numerous short and densely packed dislocations around the indentation. Consequently, it improves the substrate's load-bearing capacity and hardness. Graphene modifies the indentation behavior through the aforementioned comprehensive effects.

Return to Publications page