Orientation-dependent deformation and pop-in behavior in 3C-SiC

Understanding the relationship between crystal orientation and deformation behavior is critical for optimizing the mechanical performance of 3C-SiC in advanced applications. Here, the effect of crystal orientation on elasto-plastic deformation behavior in 3C-SiC was systematically studied using nanoindentation experiments, high-resolution transmission electron microscopy (HRTEM), and molecular dynamics (MD) simulations. Pop-in events were experimentally observed on both the (001) and (111) crystallographic planes, with the (111) plane exhibiting a higher critical pop-in load than the (001) plane. Nanoindentation tests further revealed that the (111) plane has a higher elastic modulus and nanohardness compared to the (001) plane. HRTEM analysis showed that the pop-in behavior is primarily governed by dislocation slip activity. Dislocation slip on the {111} slip plane was observed beneath the indentation for both orientations, while additional dislocation slip on the {001} slip plane, characteristic of edge dislocations, was noted for the (111) plane. MD simulations confirmed similar dislocation activity and revealed amorphization in regions of high stress concentration. Amorphization was further shown to occur within shear band zones in both crystallographic planes.