氧化硅团簇切削单晶硅粗糙峰的分子动力学模拟研究

应用分子动力学模拟方法研究了氧化硅团簇在不同的切削 深度下切削单晶硅粗糙峰的过程, 考察了切削过程中粗糙峰和氧化硅团簇形态变化、团簇的受力状况、粗糙峰原子配位数和温度分布等. 模拟结果表明: 切削深度小于0.5 nm时, 被去除的材料以原子或者原子簇形式存在, 并黏附在颗粒表面被带走; 当切削深度增大至1 nm时, 材料的去除率增大, 并形成大的切屑. 在切削过程中, 由于压力和温度的升高, 粗糙峰切削区域的单晶硅转变为类似Si-Ⅱ相和Bct5-Si相的过渡结构, 在切削过程后的卸载阶段, 过渡结构由于压力和温度的下降转变为非晶态结构.

A molecular dynamics study of silica cluster cutting single crystalline silicon asperity

The molecular dynamics simulation method is used to study the process of silica particle cutting the roughness surface at various cutting depths.The conditions of the asperity and the particle,force bearing state of particle,the distributions of coordination number and temperature in the asperity are investigated.The simulation results show that the material removal rate is small when the cutting depth is smaller than 0.5 nm,and the removed atoms sticking to the silica particle are in single atom or atom cluster form.When the cutting depth is larger than 1 nm,the material removal rate becomes larger;meanwhile a larger scrap is formed.The crystalline silicon is converted into a locally ordered transient structure which is similar to Si-Ⅱand Bct5-Si with the increases of temperature and pressure in the cutting process;then the transient structure forms amorphous silicon directly as the temperature and pressure decrease after the cutting process.