Study On Arc-electrolysis Combined Processing Technology Of Silicon Carbide Aluminum Matrix Composites

Silicon carbide aluminum matrix（SiCp/Al）composite has the advantages of low density,high specific strength,low expansion coefficient,wear resistance,corrosion resistance and so on.It has broad application prospects in aerospace,electronic packaging,automotive and other fields.However,there are some problems with traditional machining,such as low machining efficiency,serious tool wear and easy cracking.So as to realize great efficiency and high-quality machining of SiCp/Al composite materials,an arc discharge-electrolysis combined machining method is proposed in this paper.Specific research contents and results are as follows:Firstly,the arc discharge mechanism of silicon carbide aluminum matrix composites was simulated and experimentally studied with copper,45 steel,graphite and tungsten-copper alloy electrodes.The relationship between the depth of discharge pitting and each factor was studied by dynamic discharge simulation based on the melting point,thermal conductivity and specific heat capacity of the material.The results of simulation analysis have been verified by combining the material removal rate and electrode relative loss rate.Finally,the highest material removal rate（765.55mm³/min）and the lowest electrode relative loss（4.61%）was achieved with graphite electrode in the experiment.Secondly,aiming at the processing problem of waist cavity,the flow field simulation analysis,motion trajectory control strategy and experimental research were carried out in different processing states.It is concluded that the gap flow field is more uniform,when there are materials on both sides,by comparing the flow field states of different processing positions.It is concluded that the cavity can be machining without side wall residuals by optimizing the track,according to analyze the machining results of the curved track and the"back"shape track.A partial model of electrode loss was established,and the loss of electrode straight edge was0.796mm.Finally,an experimental study of the waist cavity process was conducted,using the optimized"back"shaped trajectory,while the trajectory overlap rate was set to 8%,and the resulting cavity was free of residual cuts.Finally,the electrolyte dissolution characteristics and abrasive mass fraction of SiCp/Al composites were studied in view of the problems of remelting layer and poor quality on the surface of arc discharge machining.The polarization characteristic curves of composites in different solutions were studied by electrochemical workstation,and the electrolyte formula for high-quality processing of composites was obtained as 13%Na NO₃+9%Na Cl solution.The influence of different mass fractions on the machining effect was studied,by adding 40μm diameter corundum abrasive particles into the electrolyte.Last,the suitable mass fraction was determined to be 30g/L,and the roughness was Ra3.235μm.