光学石英玻璃纳米级加工性能

Nano-processing performance of optical glass

提出了一种石英玻璃仿真模型的构建方法,并应用分子动力学（MD）仿真结合纳米压痕实验对石英玻璃进行了纳米级加工性能的研究.通过计算石英玻璃模型的密度和纳米硬度,验证了模型的准确性.对石英玻璃进行了纳米压痕实验,得到了压痕曲线并观察了纳米压痕形貌.最后,对纳米级压痕过程进行了仿真,通过计算配位数研究了损伤层的形成及扩展机理.计算得到的石英玻璃模型的纳米硬度约为9.7～10.7 GPa,密度约为2.28 g/cm^3,与实际测量结果基本一致.仿真结果表明：石英玻璃有着稳定的塑性变形和少量的弹性变形,且存在压痕的尺寸效应.当压头压下时会形成大量的原子稠密区,失去原来共价键的强度,形成损伤层;而表面形貌主要是由于压头向两侧挤压原子和压头的黏附作用形成的.仿真和实验结果都表明石英玻璃比较适合超精密加工.

A method for constructing the models of quartz glass was proposed to improve the processability of quartz glass,and Molecular Dynamics （MD） simulation combined with nanoindentation experiments were performed to research on nano-processing performance of the quartz glass.The accuracy of the model was verified by calculating the density and hardness of the quartz glass.Then the nano-indentation experiment was conducted to obtain indentation curves and to observe the morphology of indentation.Finally,a MD simulation of nano-indentation was performed and the formation and extending mechanism of a damage layer was investigated.According to the calculation of density and nano-hardness,it shows that the density is about 2.28 g/cm^3 and nanohardness is about 9.7-10.7 GPa,which is almost consistent with the experimental results.The experiments indicate that the quartz glass has a stable plastic deformation and a small amount of elastic deformation as well as the indentation size effect.When the indenter is depressed,the atomic dense area is formed.Since it losses the strength of the original covalent bonds,so the damaged layer is formed.Moreover,the surface topography is mainly formed by atoms on both sides squeezed with the indenter and the adhesion of the indenter.The simulation and experimental results show that the quartz glass is suitable for ultra-precision machining.