| As a mechanical transmission part,gear is the key part of many equipment,but the traditional metal gear in high temperature,high corrosion and high wear resistance and other special environment is prone to fracture,corrosion and wear damage,resulting in the normal production of mechanical equipment.Engineering ceramics have the excellent characteristics of high strength,high hardness,light weight,corrosion resistance and wear resistance,which can meet the requirements of mechanical equipment.The machining and forming of engineering ceramic materials is very difficult,which leads to the extremely difficult preparation of ceramic parts with complex structure.Therefore,near-final sintering is the main method to solve this problem.Therefore,in this paper,Al2O3/Zr O2/Si O2 ceramic gears without keyway and keyway were prepared by non-pressure sintering process,and their sintering process and mechanical properties were studied.Al2O3,Si O2and Zr O2 ceramic powders were mixed according to the mass ratio of55:40:5,and the ceramic gears with complete teeth and compact shape without keyway and with keyway were prepared by non-pressure sintering technology at 1300℃.The mechanical properties show that the mechanical properties of gears without keyway are slightly better than those with keyway,but the overall performance difference is small.The fracture morphology shows that the diameter of stomata is less than 1μm,and the density of stomata in the central part is higher than that in the tooth shape part.The billet compression test shows that the ceramic material has good high temperature plastic deformation ability when the temperature reaches 1200℃,the maximum flow stress is 4.53MPa,and the maximum compression strain is 25.44%.The process of dry pressing and sintering of ceramic gear without keyway and with keyway was simulated by MARC simulation software.The distribution laws of displacement,elastic recovery,equivalent stress and relative density of blank body after dry pressing were analyzed,and the distribution laws of temperature,displacement and relative density of two kinds of gears during sintering were compared.The simulation results show that the key way position density is relatively low during dry pressing and sintering,but the difference is small.The shrinkage properties of two kinds of ceramic gears were studied,and the influencing factors of the size changes of the gears before and after sintering were analyzed.The formulas for calculating the shrinkage km and kαrelative density of the gears were established.The shape correction coefficients and and of the modulus and pressure Angle were obtained by fitting.Comparative analysis shows that the keyway has no significant effect on the average relative density and shape correction factor of gears.The elastic recovery of the gear body during dry pressing was analyzed.Based on the proposed formula,the elastic recovery correction coefficient of the gear body was obtained to be 4.85. |
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