Monocrystalline silicon has anisotropic attributes due to asymmetric and non-uniform interatomic lattice structures, which affects its deformation and fracture properties. This paper aims to investigate the effect of crystallographic orientation on the material deformation and removal behavior during high speed scratching of monocrystalline silicon. A high-speed scratching setup is developed which can achieve the highest scratching speed of 40 m/s. Inclined scratching experiments are conducted on (001), (110) and (111) crystallographic planes over the speed range of 1 m/s to 30 m/s. As the scratching depth increases, the ductile-to-brittle transition of silicon at different crystallographic orientations are analyzed. The experimental results suggest that scratching in the direction of "[" ¯("1" ) "10]" on (111) plane presents the largest critical residual depth of ductile-to-brittle transition. Phase transformation from Si-I to the phases of Si-IV and a-Si dominates ductile deformation of silicon during scratching process, while scratching tests in "[" ¯("1" ) "10]" direction on (111) plane demonstrates the largest degree of material amorphization. This study can provide guidance for optimizing processing parameters of monocrystalline silicon components with different crystallographic orientations.
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