Research On The Milling Process And Influences On Surface Quality Of Single Crystal Nickel Base Superalloy

With the development of astronautical technology,the excellent properties of single crystal nickel-based superalloy shows gradually.Compared to the ordinary nickel-based superalloy,it is superior because of its excellent high temperature properties,oxidation resistance,stability in structure and use.It eliminates the grain boundary,reduces strengthening elements and becomes the main material of manufacturing aeroengine turbine blade.The blade working environment is extremely complex.It needs in a certain condition which is high temperature,high pressure,high speed in a long time.Therefore the development of the core material is one of the crucial technologies of aeroengine development both at home and abroad.Because of the particularity of the application of single crystal materials,it is required to have high stability in the service process.In recent years,due to the recrystallization of materials,the failure of blade has been discovered,so it is of great significance to explore the process of manufactureing process in order to control the recrystallization.Considering the surface roughness and milling force as the evaluation index,this paper employed the milling way,based on the cutting tool wear condition,cooling condition,processing parameters,as well as the effects on the microstructure to explore single crystal nickel-based superalloy DD5 material performance.,Since there is few special milling tools for DD5 small parts,paper carried on the optimization tool to choose more suitable for processing single crystal materials among the knives used by high temperature alloy and tool cutters recommended by manufacturers.Observe tool wear morphology in the wear process and analyze tool wear mechanism,the accumulation of tool cutting distance considered as the evaluation index.Minimum quantity lubrication and dry cutting were adopted,taking tool wear degree as criterion,to select the optimal cooling conditions for further experiments.The surface machined by different abrasion degree is tested,and the influence of tool wear on the surface integrity was analyzed.As far as the milling process of single crystal parts,use the TiAlN coating hard alloy cutter and water-based-MQL cooling conditions were used.The single factor experiment method is used to optimize the crystal orientation and cooling parameters,through measuring the size of the surface roughness and milling force to judge the merits of the different parameters.Reasons for the change of the surface quality and milling force were analyzed.The main effect graph and interaction effect of each factor were analyzed by using the response surface method center compound design.The surface roughness and milling force model are proposed in Minitab.Finally,the paper explores effects on the milling manufacturing on microstructure,surface hardness of the material processed under different cooling conditions is in comparison with each other.With the help of metallographic corrosion,microstructure of materials is observed.And then adopt heat treatment,observe microstructure in extreme condition.