Study On Forming Uniformity Control Of TC25G Titanium Alloy Blisk

The blisk is a key hot end part of the aero engine and one of the main parts which provide powers for engine,which works in the harsh service environment of high temperature and high pressure for long time.Therefore,such large forgings have extremely strict requirements on the mechanical properties of the forgings and the uniform microstructure of the forgings.With the rapid development of aerospace industry,Chinese government has put forward higher requirements for the carrying capacity and service life of the engine,conventional high-temperature titanium alloy material can no longer meet the requirements.It has great engineering application value for studying the forming process parameters of the high temperature titanium alloy TC25 G material and the shape of the pre-forging of the blisk,which improves the mechanical properties of the forgings and the distribution regularity of the microstructure uniformity effectively.In the paper,the blisk and the material of TC25 G is regarded as the research object.Studying on TC25 G materials by Thermo-physical Compression Experiment.The next step is to combine Finite Element Numerical Simulation and the model of Kriging to optimize the shape and size of Preforging.Finally,producing the Forgings and dissecting it for testing physical and chemical properties to verify the correctness of the material process parameters and the rationality of the Pre-forging shape and size by the tensile properties and microstructures of the forging.And the system research on forming law of TC25 G material and whole leaf plate forging mainly covers the following three aspects:(1)The study of material deformation parameters and cooling modes during thermoplastic deformation.The tensile properties of forging at the condition of room temperature and high temperature and microstructure were obtained through the thermal physical compression experiment of TC25 G material.The characteristics of tensile properties under different deformation,forging temperature and cooling mode were analyzed,The influence law of deformation parameters,forging temperature and cooling mold on the tensile properties and microstructure of TC25 G titanium alloy were investigated.The best technological parameters of the material were determined through the analysis of the experimental data.(2)The research of whole process numerical simulation and the control of uniformity of forging.The whole process numerical simulation is carried out by using Deform software.According to the size of the original bar,the upsetting,blank making and final forging process is arranged.To avoid the produce of forging defects and ensure perfect connection between all processes,the forging ratio of each fire is needed to be allocated reasonably.On the basis of this,the best shape of preformed blank is sought.Seven dimensional parameters of pre-forging are regarded as independent variables,The experiment is designed by Latin hypercube sampling,the equivalent strain is extracted from the forging and the corresponding response values are calculated.Finally,the size parameters of pre-forging is optimized by combining Kriging model and genetic algorithm.(4)The research of overall performance of the blisk.Forging was produced by 800 MN hydraulic press.The microstructure and mechanical properties of sample area,inner circle and outer circle and the central region were studied.The accuracy of the material process parameters and the rationality of the shape and size of the pre-forging are proved in the side by comparing the physical and chemical properties with the standard.