Research On Friction And Wear Properties And Cutting Simulation Of Porous Ceramics

Porous ceramic is a new type of engineering ceramic.The most significant feature is the existence of a large number of internal pores and its structure is very special.The porous ceramic also has many excellent properties,such as high hardness,high temperature resistance,wear resistance,etc.So it has been adopted by many fields of engineering and its friction and wear properties have also received widespread attention and research.In this paper,SiC porous ceramic material is used as the research object.Based on the friction and wear theory,indentation / scratch test theory,single abrasive grinding theory,the paper researched the friction and wear properties of SiC porous ceramic materials,the crack during indentation / scratching and the grinding process.The main research work includes the following aspects:Taking SiC porous ceramic material as the research object,its friction and wear mechanism of were studied by means of experiment and simulation.The pin-plate test was carried out on the MMW-1A friction and wear tester.The influence of load and rotational speed on the friction coefficient and SiC ceramic wear were studied by the method of orthogonal experimental design.Through the variance analysis of the wear amount and the friction coefficient,it is concluded that the load has the greatest influence on the wear amount of SiC ceramics and the rotation speed has the greatest influence on the friction coefficient.When SiC ceramic is matched with 45 steel,the wear mechanism of SiC ceramic is mainly abrasive wear,furrow wear and adhesive wear.The large number of through holes on the surface and inside of SiC porous ceramic,the test results have relatively large errors and no surface cracks can be observed Based on the theoretical basis of the indentation testing method,ABAQUS finite element software is used to simulate the indentation process of diamond indenter and SiC ceramic specimen.The simulation results show that during the loading process,SiC ceramics first produce plastic deformation.With the development of plastic deformation,the material under the indenter forms a central crack where the stress is maximum.As the indentation depth increases,the central crack will continue to expand to form a radial crack.During the unloading process,the stress under the indenter gradually decreases,but the stress at the indentation edge does not decrease,so the radial cracks will continue to expand.Based on the third chapter and the principle of scratch test,the friction performance and the crack generation mechanism of SiC ceramics were studied.Scratch tests of diamond and SiC ceramics were performed on MMW-1A type friction and wear tester.The friction coefficient and the width of scratches were analyzed with the load and speed as variables and the surface of the SiC ceramic was observed with a metallographic microscope.The wear mechanism and crack generation and expansion mechanism of the SiC ceramic under scratching were analyzed.The test results show that the friction coefficient is gradually increasing with the increase of the load or the increase of the speed,but compared with the speed,the effect of the load on the friction coefficient is more obvious.At the same time,the scratch width of diamond when scratched SiC ceramic also increases with the increase of speed.During the scratch process,the positive pressure causes the SiC porous ceramic particles to separate,and the shear stress separates the SiC porous ceramic particles in the tangential force direction.Based on single abrasive grain grinding theory,the geometric model of diamond abrasive grains and SiC ceramic workpiece was established by ABAQUS finite element software.The grinding process was simulated based on the Drucker-Prager constitutive model.The simulation results show that during the grinding process,the maximum principal stress first increases,then decreases,finally tends to a stable trend.With the increase of speed,the wider the area of stress concentration,which makes the workpiece more prone to deformation and the deformation becomes more and more obvious.At the same time,the grinding force is also increasing.But with the appearance of debris,the grinding force will fluctuate in a certain range,and the grinding force will tend to be stable at this time.