摘要
激光抛光是一种非接触式等材超精密抛光方法,在单晶硅的激光抛光实验中观测到的“山”字形表面形貌演化规律无法用传统的表面张力和马兰戈尼效应主导的熔池流动理论解释,研究发现塑性变形在单晶硅表面形貌演化中扮演关键角色。通过对残余应力的测量以及截面TEM的观测,发现塑性变形出现在材料熔化之前。综合考虑熔化前的塑性变形及熔化后的表面张力和马兰戈尼效应,对单点激光抛光后中心凸起及边缘堆积的“山”字形表面形貌的演化进行了探究。以此为前提,对不同激光光斑扫描间距下受塑性变形影响的表面形貌的演变进行了分析。当扫描间距小于2.5μm时,塑性变形产生的中心凸起可以被后续激光脉冲所抛光,单晶硅表面粗糙度从4.04 nm降低至0.34 nm。经过研究,总结出激光抛光中塑性变形与毛细流动共同作用下的表面形貌演化规律与机理,为激光抛光的参数选择提供理论指导。
Laser polishing is a non-contact ultra-precision polishing method for equal materials.The evolution of the“trident”surface morphology observed in experiments cannot be explained by the traditional theory of surface tension and Marangoni effect dominant molten pool flow.It is found that the plastic deformation plays a critical role in surface topography evolution.The residual stress is measured by XRD and the section is observed by TEM,which shows that the plastic deformation occurs before the material melts in laser polishing.Considering plastic deformation before melting,and surface tension,Marangoni effect after melting,the“trident”surface topography of the center bulge and the edge piling up after single point laser polishing is investigated.Based on this premise,the surface morphologies affected by plastic deformation are analyzed at different scanning intervals.When the scanning intervals are less than 2.5μm,the central bulge caused by plastic deformation can be polished by subsequent laser pulses,and the surface roughness of monocrystal silicon decreases from 4.04 nm to 0.34 nm.The evolution law and mechanism of surface topography under the plastic deformation and capillary flow in laser polishing are summarized,which provides theoretical guidance for parameter selection of laser polishing.
作者
李涛
黄惟琦
龙归
杨思铄
张建国
肖峻峰
许剑锋
LI Tao;HUANG Weiqi;LONG Gui;YANG Sishuo;ZHANG Jianguo;XIAO Junfeng;XU Jianfeng(School of Mechanical Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074;State Key Laboratory of Intelligent Manufacturing Equipment and Technology,Huazhong University of Science and Technology,Wuhan 430074)
出处
《机械工程学报》
EI
CSCD
北大核心
2023年第21期52-64,共13页
Journal of Mechanical Engineering
基金
国家自然科学基金(51705172,51905194,52225506,52188102)
中央高校基本科研业务费专项资金(2020kfyXJJS085)资助项目。
关键词
激光抛光
塑性变形
形貌演变
超精密加工
laser polishing
plastic deformation
topography evolution
ultra-precision machining
