Molecular dynamics study on surface formation and phase transformation in nanometric cutting of β-Sn

Atomic motion and surface formation in the nanometric cutting process ofβ-Sn are investigated using molecular dynamics(MD).A stagnation region is observed that changes the shape of the tool edge involved in nanometric cutting,resulting in a fluctuation in the cutting forces.It is found that single-crystal tin releases the high compressive stress generated under the tool pressure through slip and phase transformation.The tin transformation proceeds from aβ-Sn structure to a bct-Sn structure.The effects of the cutting speed,undeformed chip thickness(UCT)and tool edge radius on material removal are also explored.A better surface is obtained through material embrittlement caused by a higher speed.In addition,a smaller UCT and sharper tool edge help reduce subsurface damage.