An Evaluation of nanoindentation-induced displacement burst and collective dislocation motion based on discrete dislocation mechanics and elastic energy of dislocations

Tsuru, Tomohito   ; Shibutani, Yoji*

Abrupt growth of displacement observed in the relationship between indent load and indent depth in nanoindentation of crystalline materials, so-called displacement burst, has been recognized as one of the representative examples for the nanoplastic behavior. This behavior corresponds to the early stage of the plastic deformation and has greatly been influenced by the collective dislocation emission. In the present paper, we construct two models; first one is the computational model of dislocation mechanics, and second one is simplified energetic model of the first displacement burst. As the result of these models, it is found that surface step corresponding to each dislocation causes significant displacement burst and that more than one hundred high-density dislocations are emitted simultaneously.