Understand anisotropy dependence of damage evolution and material removal during nanoscratch of MgF_(2) single crystals  

作　　者：Chen Li Yinchuan Piao Feihu Zhang Yong Zhang Yuxiu Hu Yongfei Wang 

机构地区：[1]State Key Laboratory of Robotics and System(HIT),Harbin Institute of Technology,Harbin 150001,People’s Republic of China

出　　处：《International Journal of Extreme Manufacturing》2023年第1期236-252,共17页极端制造（英文）

基　　金：supported by the National Natural Science Foundation of China (52005134&51975154);China Postdoctoral Science Foundation (2022T150163, 2020M670901);Self-Planned Task (No. SKLRS202214B) of State Key Laboratory of Robotics and System (HIT);Heilongjiang Postdoctoral Fund (LBH-Z20016);Shenzhen Science and Technology Program (GJHZ20210705142804012);Fundamental Research Funds for the Central Universities(FRFCU5710051122);Open Fund of ZJUT Xinchang Research Institute

摘　　要：To understand the anisotropy dependence of the damage evolution and material removal during the machining process of MgF_(2) single crystals,nanoscratch tests of MgF_(2) single crystals with different crystal planes and directions were systematically performed,and surface morphologies of the scratched grooves under different conditions were analyzed.The experimental results indicated that anisotropy considerably affected the damage evolution in the machining process of MgF_(2) single crystals.A stress field model induced by the scratch was developed by considering the anisotropy,which indicated that during the loading process,median cracks induced by the tensile stress initiated and propagated at the front of the indenter.Lateral cracks induced by tensile stress initiated and propagated on the subsurface during the unloading process.In addition,surface radial cracks induced by the tensile stress were easily generated during the unloading process.The stress change led to the deflection of the propagation direction of lateral cracks.Therefore,the lateral cracks propagated to the workpiece surface,resulting in brittle removal in the form of chunk chips.The plastic deformation parameter indicated that the more the slip systems were activated,the more easily the plastic deformation occurred.The cleavage fracture parameter indicated that the cracks propagated along the activated cleavage planes,and the brittle chunk removal was owing to the subsurface cleavage cracks propagating to the crystal surface.Under the same processing parameters,the scratch of the(001)crystal plane along the[100]crystal-orientation was found to be the most conducive to achieving plastic machining of MgF_(2) single crystals.The theoretical results agreed well with the experimental results,which will not only enhance the understanding of the anisotropy dependence of the damage evolution and removal process during the machining of MgF_(2) crystals,but also provide a theoretical foundation for achieving the high-efficiency and low-damage processin

关 键 词：anisotropy dependence damage evolution stress field crack propagation NANOSCRATCH MgF_(2)single crystal 

分 类 号：TQ132.2[化学工程—无机化工] TB383.1[一般工业技术—材料科学与工程]