Effect of temperature on ductile-to-brittle transition in diamond cutting of silicon

Ultra-precision machining of single-crystal silicon can be realized by applying single-point diamond turning with micro-laser-assisted machining technology, through which the ductility of silicon can be enhanced. However, it is difficult to explain the role of temperature accurately in such technology in a traditional manner. In this study, numerical simulation technology was utilized to obtain the temperature distribution conquering the limitations of the traditional measurement method. Besides, a diamond grooving simulation model considering the temperature effect was developed using the smoothed particle hydrodynamics (SPH) algorithm. The shortcoming of the accuracy of calculation brought by applying the finite element method can be overcome effectively. By analyzing the evolutions of cutting force, the ductile-to-brittle transition behavior was distinguished. The comparison of the quantitative values of critical depths of cut between the simulations and grooving experiments corroborated the high accuracy of the as-established SPH model. In addition, the significance of temperature on ductile-to-brittle transition is successfully divulged. The simulation results demonstrate that the critical depth of cut of ductile-to-brittle transition increases in pace with an increase in temperature due to the thermal softening effect, indicating the enhancement of ductile response of the material. This study provides a novel method for the investigation of ductile-to-brittle transition mechanism and the optimization of processing parameters of single-crystal silicon.