Requirements for Ductile-mode Machining Based on Deformation Analysis of Mono-crystalline Silicon by Molecular Dynamics Simulation

To obtain scientific guidelines for ductile-mode machining, nano-indentation, nano-bending, and nano-machining of defect-free mono-crystalline silicon are investigated by molecular dynamics simulation. Results show that amorphous phase transformation of silicon is a key mechanism for inelastic deformation, and stable shearing of the amorphous is necessary for ductile-mode machining. Stress analysis suggests that stable shearing takes place under a compressive stress field. In practice, a sharp cutting edge tool with a large negative rake angle should be used for effective ductile-mode machining, and vibration machining should be applied for larger depths of cut as it enlarges the amorphous region in front of the cutting edge.