Evolution of plasticity in nanometric cutting of Fe single crystals

Using molecular dynamics simulation we study the generation and evolution of plasticity and defects in orthogonal cutting of an Fe single-crystalline workpiece. We focus on the (1 1 1)[112¯] cutting geometry. Dislocations are generated at the primary shear zone with Burgers vector b = 1/2〈11 1〉 and the dislocation line oriented parallel to the cutting edge. They are emitted along their glide systems deep into the material. The chip - beyond the primary shear zone - is initially defect-free; upon continued cutting point defects and threading dislocations enter the chip. Besides the emitted dislocations, an extended defect (twin boundary) is created immediately below the cutting edge in the workpiece. The cut surface strongly roughens and deviates from the original (1 1 1) orientation.