New insights into the deformation mechanism of orientation-dependent nanoindentation behaviours

Abstract

Nanoindentation has been widely used to access the micro-/nanomechanical properties of materials. However, the contribution of micro-texture evolution to the anisotropic surface topography, the correlation of dislocation density characteristics with the orientation-dependent plastic volume, and the specifics of inherent slip activities, are still not fully elucidated up to now.Herein, nanoindentation simulations were performed on (001)-, (101)- and (111)-oriented single-crystal aluminium. Dominant slip systems are exactly determined for each surface pile-up for the first time. Moreover, lattice rotation facilitates the formation of pile-ups. The anisotropic plastic volume is controlled by the preference of intrinsic dislocation movement. In (001) sample, dislocations prefer to propagate along the free surface instead of into the depth of the sample, causing its most obvious pile-ups.