碳化硅纳米抛光亚表面损伤机理的分子动力学模拟  

A Molecular Dynamics Simulation on the Subsurface Damage Mechanism in the Nano-polishing Process of Silicon Carbide

作　　者：华东鹏 周青 王婉[1,2] 李硕 王志军 王海丰[1,2] HUA Dongpeng;ZHOU Qing;WANG Wan;LI Shuo;WANG Zhijun;WANG Haifeng(State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072;Center of Advanced Lubrication and Seal Materials,Northwestern Polytechnical University,Xi’an 710072)

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072 [2]西北工业大学先进润滑与密封材料研究中心,西安710072

出　　处：《机械工程学报》2024年第5期231-240,共10页Journal of Mechanical Engineering

基　　金：国家自然科学基金(52175188);西北工业大学博士论文创新基金(CX2022009);陕西省重点研发计划(2023-YBGY-434);西安交通大学金属材料强度国家重点实验室(20222412)资助项目。

摘　　要：碳化硅(SiC)在表面微纳加工过程中损伤机理的研究不足限制了SiC的加工表面质量及应用,因此了解不同抛光参数下SiC的损伤机理对提高SiC的纳米加工表面质量具有重要意义。采用分子动力学模拟研究了单晶SiC在纳米抛光过程中的亚表面损伤机理,并考虑了抛光速度和抛光深度的影响。结果表明,随着抛光深度的增加,SiC的去除机制逐渐由以黏附和犁沟机制为主转变为以切削机制为主。微裂纹通过滑移面层间Si-Si键的断裂形成于滑移带尖端。此外,抛光深度越大,工件吸收动能的效率越高,从而导致抛光速度对工件温度和力学性能的影响越显著。因此较小的抛光深度和较大的抛光速度可以获得更好的表面加工质量。这些结果为解释SiC纳米抛光实验中的变形损伤机理提供了新的见解,可以指导设计纳米抛光工艺以获得更好的SiC表面质量。The lack of study on the damage mechanism of silicon carbide(SiC)during surface micro/nano-machining limits the machined surface quality of SiC and application.Therefore,it is important to understand the damage mechanism of SiC under different polishing parameters for improving the nano-machined surface quality of SiC.The mechanism of subsurface damage of single crystal SiC during nano-polishing is studied by molecular dynamics simulation,and the effects of polishing speed and depth are considered.The result shows that the removal mechanism of SiC gradually changes from adhesion and ploughing mechanisms to cutting mechanisms with the increase of polishing depth.The microcracks are formed at the tip of the slip band through the fracture of the interlayer Si-Si bond on the slip surface.In addition,the greater polishing depth causes the higher efficiency of the workpiece in absorbing kinetic energy,resulting in the more significant impact of polishing speed on the workpiece temperature and mechanical properties.Therefore,better machined surface quality can be got by smaller polishing depth and larger polishing speed.These results provide new insights into the mechanism of deformation and damage for SiC in nano-polishing experiments,and can guide the design of nano-polishing processes to achieve better SiC surface quality.

关 键 词：碳化硅 纳米抛光 微裂纹 亚表面损伤 分子动力学模拟 

分 类 号：O77[理学—晶体学] O33