Research On Surface Damage Of Al₂O₃/TiC Ceramic Material By Micro-grinding Based On Discrete Element Method

Ceramic materials have many excellent properties and are widely used in mechanical manufacturing,aerospace,optics,biomedicine and other engineering fields.Alumina based ceramic material has the characteristics of high strength,high hardness,low fracture toughness and high brittleness.In the process of precision machining and ultra-precision machining with diamond grinding wheel,the surface and sub-surface of the workpiece are easy to produce micro-cracks,dislocations and other processing damage,thus affecting the surface integrity and mechanical properties of the processed specimens.On alumina base TiC ceramic materials in order to face processing surface micro grinding process is of good integrity,and efficient quality of low damage based on the discrete element method of Al₂O₃/TiC ceramic material to produce in the process of micro grinding micro cracks,dislocation and other surface damage by adopting the combination of numerical simulation and experimental method were studied.Main research contents:（1）Taking Al₂O₃/TiC ceramic materials as the research object,the single-abrasive cutting model is established,the material removal method and crack propagation mechanism are analyzed,and the surface damage crack depth model is established based on indentation fracture mechanics in the single-abrasive cutting process.（2）The two-dimensional and three-dimensional BPM models of Al₂O₃/TiC ceramic materials were established by the particle flow discrete element software PFC2D and 3D,and the established discrete element models were parameterized and calibrated by uniaxial compression test,three-point bending test and Brazilian splitting test,so as to obtain a model matching the mechanical properties of Al₂O₃/TiC ceramic materials in the experiment.（3）The two-dimensional machining model of Al₂O₃/TiC ceramic single abrasive particle cutting process and the discrete element model of 3D multi-abrasive grinding wheel micro-grinding process were established.The discrete element PFC2D and 3D software were used to simulate the cutting process of single grain and multi-grain grinding wheels,and the variation rules of grinding depth,feed speed and grinding particle size of grinding wheel on the number and depth of surface damage cracks of the workpiece were studied.（4）Microgrinding experiment of Al₂O₃/TiC ceramic end surface was conducted to study the change of grinding force caused by the change of different technological parameters in the process of microgrinding,and the surface damage and surface roughness were detected by scanning electron microscopy and non-contact surface topography,and the influence of the change of different technological parameters on the surface damage was analyzed.