| The single crystal blade is the core component of the hot end of an aeroengine,its manufacturing process is one of the remarkable signs to measure the level of an aeronautical industry in a country.Based on the analysis of the manufacturing technology and development status of single crystal blade at home and abroad,the paper focused on the low yield of investment casting,combined with the magnetic levitation smelting of superalloy and sol idification process of single crystal blade,carried out optimization simulation research.In the process of rapid precision casting,the factors influencing the effect of spiral crystal selection of DD5 alloy were analyzed,and the simulation of the evolution process of the structure of the crystal selector was carried out and the related experiments were carried out.Dei:ails are as follows:Firstly,based on the theory of magnetic field intensity and fluid-solid coupling heat dissipation in superalloy smelting,the influence of the shape and height of the bottom of the cold crucible on its magnetic field intensity and energy utilization ratio,as well as the influence of cooling system structure on its heat dissipation were analyzed.With the help of the magnetic field module in Workbench,the magnetic field strength and energy utilization ratio of the cold crucible with bottom shape and height are analyzed.Combining with the fluid-solid coupling module,the distribution of flow field,pressure field and temperature field of the cold crucible split cooling system were analyzed.The optimum bottom shape,height and cooling system structure of the cold crucible were obtained.Secondly,based on the theory of directional solidification of single crystal blade and evcolution of microstructure of spiral crystal selector,the influence of withdrawal rate on soli dification process of single crystal blade and evolution of microstructure of spiral crystal selcector were analyzed.With the help of ProCAST software and CAFE module,the effects of different withdrawal rate on temperature field,paste zone,secondary dendrite arm spacing,structure evolution and grain number change in spiral separator during solidification of single crystal blades were analyzed,and the optimum withdrawal rate was obtained at about 5 mm/min.Finally,based on the rapid fabrication of spiral crystal selector mold by surface shaping and light curing,the spiral crystal selector properties at different withdrawal rate were studied.By observing the grain size,metallographic structure and dendrite size of different sections in the induced and selected segments,it was suggested that the optimum withdrawal rate should be about 5 mm/min under specific technological conditions. |
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