Abstract:Owing to its excellent thermal conductivity, high breakdown voltage, and high-temperature stability, 4H-SiC is a promising material for power electronics and high-frequency devices. However, its extreme hardness and low fracture toughness cause severe subsurface damage and rapid tool wear during nanoscale cutting. Thermally assisted machining can improve machinability by promoting plastic deformation and enhancing efficiency; therefore, understanding the temperature-dependent material removal mechanism in nanometric cutting of 4H-SiC is essential. This study employs molecular dynamics simulations to systematically investigate the cutting mechanical behavior, surface morphology, subsurface damage, stress distribution, and dislocation evolution of 4H-SiC under different cutting temperatures (100–1000 K). The results show that the average cutting forces decrease markedly with increasing temperature. At 1000 K, the tangential and normal forces are reduced by 15.4% and 29.3%, respectively, compared with those at room temperature (300 K). Cutting at intermediate temperatures (500–600 K) effectively suppresses subsurface damage, alleviates stress concentration, and reduces dislocation density. However, excessively high temperatures (≥800 K) aggravate damage and broaden the stress distribution due to enhanced dislocation multiplication and tangling. This work reveals the plastic removal mechanism and damage evolution of 4H-SiC under different temperatures, offering a theoretical basis for efficient, low-damage nanometric cutting.