Study On The Material Characteristics And Corrosion Characteristics Of Aluminum Base Large Length-diameter Ratio Hole Made By Casting

The material with large aspect ratio hole has important application value in the cooling water channel of engine fuel injection nozzle,injection molding,stamping and other molds.At present,the application of mature electron beam processing and 3 D printing is restricted by the problems of limited process and high cost.In this paper,on the basis of the large aspect ratio hole material prepared by the casting method accumulated in the laboratory for many years,carbon fiber is used as the core material,aluminum and its alloy are used as the matrix material,and the large aspect ratio array hole material is prepared according to actual needs.And U-shaped hole material,the effects of experimental temperature and Si element on pore formation characteristics and corrosion characteristics are analyzed in detail.To investigate the effect of Si element content on the hole formation characteristics of large aspect ratio fine holes,a pore material with hole size of 0.3 mm? hole spacing of 2 mm was prepared under the condition of different Si content.It is found that the change of element content in matrix has an important effect on the filling height and wall roughness of samples.When the Si content is 12 wt.%,the infiltration coefficient increases with the decrease of melt surface tension,and the filling effect is optimal.The height of the prepared array hole material can reach 47 mm,and the roughness of the hole wall can be reduced to 74.Another important factor for roughness is the experimental temperature.In this paper,the effect of pouring temperature on the roughness of hole wall is investigated by changing pouring temperature.As the temperature increases,the filling capacity of melt is improved,and the roughness of hole wall can reach 73 when the pouring temperature is 775?.However,with the further increase of temperature,the reaction between carbon fiber and aluminum will occur.The roughness increases significantly.In order to further explore the effect of roughness on the practical application of large aspect ratio hole materials,especially on corrosion resistance.By amplifying the pore size,the corrosion law of U-shaped hole materials prepared at different temperatures is analyzed in detail.The wall roughness of U-shaped hole and fine hole is the same as that of temperature.At775?,the roughness will reach the minimum value of 76.At this time,it shows good resistance to spalling corrosion and intergranular corrosion.However,with the increase of temperature,the corrosion performance decreases obviously.This is because as the temperature rises,it will not only cause the carbon fiber to react with the matrix to form carbides,but also cause the obvious segregation of Si elements at the hole wall,which will seriously reduce the corrosion resistance of the U-shaped hole.When the experimental temperature is 800?,not only will it cause severe spalling corrosion,but the depth of intergranular corrosion will also reach 220?m.