Micromechanical and Macroscopic Modelling (MMM)
Depth-sensing ductile and brittle deformation in 3C-SiC under Berkovich nanoindentation
L. Zhao, J. Zhang, J. Pfetzing-Micklich, M. Alam, A. Hartmaier.
Materials & Design, Elsevier, 197, 109223, (2021)
The interplay between ductile and brittle deformation modes in hard brittle materials exhibits a strong size effect. In the present work, indentation depth-dependent deformation mechanisms of single-crystal 3C-SiC under Berkovich nanoindentation are elucidated by finite element simulations and corresponding experiments. A novel finite element framework, that combines a crystal plasticity constitutive model for describing dislocation slip-based ductile deformation and a cohesive zone model for capturing crack initiation and propagation-induced brittle fracture, is established. The utilized parameters in the crystal plasticity model of 3C-SiC are calibrated according to the load-displacement curves obtained from corresponding Berkovich nanoindentation experiments. Subsequent finite element simulations and experiments of nanoindentation jointly reveal co-existing microscopic plastic deformation and brittle fracture of 3C-SiC at different indentation depths, which significantly affect the observed macroscopic mechanical response and surface pile-up topography. In particular, the predicted morphology of surface cracks at an indentation depth of 500 nm agrees well with experimental observation, and the correlation of crack initiation and propagation with surface pile-up topography is theoretically analyzed.
Keyword(s): 3C-SiC; berkovich nanoindentation; brittle fracture; finite element simulation; crystal plasticity; cohesive zone model