Research On Constitutive Equations For Tc6 And Microstructure Simulation Of Blade

A blade is one of the most important components in aero-engines. It plays the key role of energy conversion. The process of blade precision forging affects the mechanical property. Its internal microstructure may undergo a series of changes, and the microstructure evolution will influence the macro deformation behavior of the material. Therefore, investigation into the influence of deformation parameters on the properties of blade through deformation-heat transfer-microstructure evolution coupling simulation of blade forging process is important to get ideal properties of forgings. In this thesis, the precision forging process rule and microstructure evolution of TC6 titanium alloy blade in an engine are analyzed and studied through 3D finite element numerical simulation. The research results have some theoretical significance and practical values for the development of the forming technology of the blade. The main contents of this paper are listed as follows:(1) Through thermal simulation compression experiments, the effects of hot deformation parameters on flow stress and microstructure of TC6 titanium alloy have been investigated. The results show that the strain rate affects the degree of re-crystallization of the material and then the extent of grain refinement. Moreover, the flow stress increases with the increasing strain rate. Deformation temperature affects the content and average grain size of primary a phase, and the flow stress decreases with increasing deformation temperature. The grain size of TC6 titanium alloy can be refined with the increase of deformation.(2) Constitutive equation during hot deformation and the equation of microstructure dynamic re-crystallization for TC6 titanium alloy have been established and verified through the experimental data, the average error between the equation and experimental data is smaller than 16.1%.(3) In order to have the function to simulate microstructure evolution, microstructure evolution model of TC6 alloy has been embedded in user subroutine using Absoft-Pro-Fortran language on the platform of DEFORM-3D. A numerical simulation of hot upsetting process for cylinder billet has been carried out using secondary developed software. The simulated and experimental results have been compared to prove the reliability of the secondary developed software.(4) Precision forging process of TC6 titanium alloy blade has been simulated by using the secondary developed software. The forming rule and microstructure distributing rule of blade forging during procedures of cogging, pre-forging and finish forging have been obtained at different deformation conditions. Process parameters of TC6 blade forging are optimized by analyzing the simulation results to obtain reasonable process parameters.