Evolution Of Microstructure And Mechanical Pronerties Of Ti-Al-V-Fe Titanium Alloy During The Forward And Backward Composite Spinning

With the development of aerospace and national defense industries,the demands of equipment lightweight,strength and low cost are developing,which requires higher requirements for the improvement of performance and cost reduction of titanium alloy barrel.With its unique advantages of local loading forming,strong spinning has become one of the best methods for the preparation of tube parts with excellent performance.But the spinning process is complicated.At present,the research on the strong spinning of titanium alloy cylinder is mainly focused on the forming of parts,the control of size accuracy and forming defects,and the research on the microstructure evolution and mechanical properties of the spinning process of the cylinder is less.With the violent metal plastic flow,the special deformation texture will be formed during the strong spinning process.The evolution of these textures is one of the key factors affecting the performance of titanium alloy spinning cylinder,so it is urgent to carry out relevant research.In this paper,the microstructure,texture evolution and strengthening mechanism of low cost titanium alloy(Ti-4.2Al-2.8V-1.8Fe)were studied.Based on the analysis of the material thermal processing performance through the thermal compression test,a new spinning process is developed: Forward and Backward Spinning(FBS),Forward and Backward Cross Spinning(FBCS),and the strong spinning test is completed by combining the known Unidirectional Spinning(UDS)and cross spinning(CS).In addition,the change of the microstructure and performance of spinning process is analyzed by OM,SEM,XRD and other analysis methods.The finite element simulation analysis of spinning process is carried out by ABAQUS software.On this basis,the simulation of texture modeling of multi-channel spinning process is carried out based on viscoplastic self consistent model.The results show that the new technology(FBCS/FBS)has a certain effect on the improvement of the circumferential mechanical properties of titanium alloy cylinder parts compared with one-way spinning.From the uniaxial tensile test of small sample,the new technology has increased the tensile strength of 8-71 MPa compared with the one-way spinning pressure;The texture of the base surface of the cross cross fbcs is weak and the cross spinning pressure is the second,and the UDS is similar to that of the FBS.It is further verified that texture distribution is one of the factors affecting the improvement of circumferential properties.Different spinning processes will obviously affect the deformation evolution of metals in multi-channel spinning process,especially the cyclic shear strain.The cyclic shear strain of the UDS and positive and FBCS is accumulated with the number of cycles.And the CS and FBS are in fluctuating state due to the process characteristics.In addition,the introduction of positive and negative spinning technology can effectively alleviate the arch defects at the mouth.The viscoplastic self consistent model is applied to the multi pass spinning process for the first time,and the texture evolution was analyzed.The predicted results of the simulated texture are in good agreement with the experimental results.The activation of the micro slip system is analyzed with the help of the model.It is found that the change of spinning process has a significant effect on the evolution of the activation of the slip system in the spinning process.