Simulation And Experimental Study On Regularity Of Spark Plasma Sintering And Forming

Spark plasma sintering is a high-tech technology to prepare new materials,whichhas risen since the1990s，and has already been widely used in many fields in recent yearsfor its unique advantages. The SPS process of non-conductive materialSialon/Si2N2O ceramic and conductive material Ti was simulated and analyzedcomparatively by MARC software, Meanwhile, Simulation and experimental research onthe extrusion forming process of wear-resistant ceramic spherical parts of a model rocketwith electric field assisting were carried out. As a result, the basic rules of spark plasmasintering and the extrusion forming process with electric field assisting were obtained.Via spark plasma sintering technology，the Sialon/Si2N2O ceramic was sintered at thesame heating rate under the condition of1523K,1623K and1723K with5min dwellingtime. The variation curves of sintering voltage and displacement with time were obtainedvia the test. The SPS process of non-conductive material Sialon/Si2N2O ceramic issimulated on the basis of the experiment results; the temperature and relative densitydistribution rules of the sample were analyzed in initial heat preservation stage and finalheat preservation stage.The simulation and experimental research on non-conductive material Sialon/Si2N2Oceramic and conductive material Ti were carried out under the same sintering condition.The temperature field differences were obtained in the process of sintering.Comparedwith non-conductive material Sialon/Si2N2O, the heating rate of conductive material Ti ishigher but its temperature distribution is more inhomogeneous. Meanwhile, the effect ofgraphite felt and die size on the temperature field is analyzed. The simulation results showthat the graphite felt can effectively reduce the heat loss caused by radiation and improvethe sample heating rate. The sintered products of the small difference in temperature andhigh quality can be obtained by using reasonable die size.`Under the condition of1773K, The simulation and experimental research on theextrusion forming process of wear-resistant ceramic spherical parts of a model rocket withelectric field assisting were carried out. The Sialon/Si2N2O ceramic can obtain lowtemperature and high strain rate. The temperature of the contact position of the spherical part and the upper pressure head is the highest and the temperature of the contactposition of the spherical part and the lower pressure head is the lowest in the extrusionprocess. The value of the equivalent strain of the spherical part is smaller and is less than10MPa in the final forming state.The overall resistance variation of sintering system on non-conductive materials inspark plasma sintering is studied based on experiment data of Sialon/Si2N2O ceramic. Thechange curves of the overall resistance with the sintering temperature and the initial heightof powder are obtained.