Nanoindentation study on the influence of nanovoid spatial distribution on local plastic deformation behavior

• This study focuses on the impact of microvoids on material properties by examining indentation force, dislocation behavior, and localized plastic deformation. • During the analysis of dislocation evolution, it was found that in materials containing microvoids, dislocation growth tends to occur towards the voids. • By analyzing the hardness of materials with microvoids and the factors affecting it, an empirical equation was derived that relates hardness to these influencing factors, considering the weight of each factor. This study employs large-scale molecular dynamics simulations to investigate the influence of spherical nanovoids on the nanoindentation response of nickel single crystals. The interaction between nanovoid geometry—varied in size and depth—and the resulting plastic deformation behavior is systematically examined. The results show that nanovoids significantly affect dislocation evolution, acting as dislocation sinks. The absorption capacity increases with nanovoid size and proximity to the free surface. Post-nucleation dislocations propagate toward nanovoids, indicating a spatial coupling between defects and plastic slip activity. Mechanically, nanovoids cause a size- and location-dependent reduction in hardness, with surface-proximal and larger nanovoids having a more pronounced softening effect. Deeply embedded nanovoids show negligible impact. An empirical relation quantifies the hardness degradation based on nanovoid geometry, showing strong agreement with simulation data. These findings provide insights into defect-plasticity interactions and contribute to the design and performance evaluation of nickel-based materials in micro/nanoscale applications.