Material Removal Characteristics of Single-Crystal 4H-SiC Based on Varied-Load Nanoscratch Tests  

作　　者：Kun Tang Wangping Ou Cong Mao Jie Liang Moke Zhang Mingjun Zhang Yongle Hu 

机构地区：[1]Hunan Provincial Key Laboratory of Intelligent Manufacturing Technology for High-performance Mechanical Equipment,Changsha University of Science and Technology,Changsha 410114,China

出　　处：《Chinese Journal of Mechanical Engineering》2023年第4期125-138,共14页中国机械工程学报（英文版）

基　　金：Supported by National Natural Science Foundation of China(Grant No.51405034);Changsha Municipal Natural Science Foundation of China(Grant No.kq2202200);Hunan Provincial High-tech Industry Science and Technology Innovation Leading Program of China(Grant No.2022GK4027).

摘　　要：Single-crystal silicon carbide(SiC)has been widely applied in the military and civil fields because of its excellent physical and chemical properties.However,as is typical in hard-to-machine materials,the good mechanical properties result in surface defects and subsurface damage during precision or ultraprecision machining.In this study,single-and double-varied-load nanoscratch tests were systematically performed on single-crystal 4H-SiC using a nanoindenter system with a Berkovich indenter.The material removal characteristics and cracks under different planes,indenter directions,normal loading rates,and scratch intervals were analyzed using SEM,FIB,and a 3D profilometer,and the mechanisms of material removal and crack propagation were studied.The results showed that the Si-plane of the single-crystal 4H-SiC and edge forward indenter direction are most suitable for material removal and machining.The normal loading rate had little effect on the scratch depth,but a lower loading rate increased the ductile region and critical depth of transition.Additionally,the crack interaction and fluctuation of the depth-distance curves of the second scratch weakened with an increase in the scratch interval,the status of scratches and chips changed,and the comprehensive effects of the propagation and interaction of the three cracks resulted in material fractures and chip accumulation.The calculated and experimental values of the median crack depth also showed good consistency and relativity.Therefore,this study provides an important reference for the high-efficiency and precision machining of single-crystal SiC to ensure high accuracy and a long service life.

关 键 词：Single crystal silicon carbides Varied-load nanoscratch Material removal Crack propagation 

分 类 号：TB301[一般工业技术—材料科学与工程]