Investigations on thermal effects on scratch behavior of monocrystalline silicon via molecular dynamics simulation

•High temperatures can improve material removal rate.•Scratch force reduces as temperature rises.•Frictional coefficient first increases, and an abrupt decline occurs beyond 200 K.•Low temperature is beneficial to the formation and stability of bct5-Si. Scratching along monocrystalline silicon [110] crystal orientation at the temperature from 1 K to 1000 K were carried out by molecular dynamics (MD) simulations to study thermal effects on machining performance and subsurface damage mechanisms. Scratch force and phase transformation at different temperatures were studied. The results reveal that high temperatures can induce small scratch force and high material removal rate. Amorphous silicon can always appear beneath the scratched surface, irrespective of temperature. The generation and stability of bct5-Si show high dependence on temperature. At the temperature from 1 K to 500 K, there is bct5-Si generated beneath amorphous silicon during the scratch process, which is not found above 600 K. Bct5-Si beneath amorphous silicon layer keeps stable after scratching at 1 K and 100 K, while is transformed into amorphous silicon at the temperature from 200 K to 500 K.