Extrusion Forming And Microstructure Changes Of Titanium Alloy TC4 Thin-walled Cylinder

As a new metal material,titanium alloy TC4 has been widely used in military,medical,aerospace and other fields,and by virtue of its good performance to replace steel and other traditional materials,to achieve weight reduction,energy conservation,material reduction and other purposes.At present,domestic hot battery shell materials still choose stainless steel and other steel materials,its main processing method is mechanical processing,not only occupy most of the quality of the hot battery and the traditional processing caused a great waste of materials.Therefore,it has become an important research direction to choose new materials and processing methods to reduce the weight of thermal battery shell and improve the material utilization rate.In this paper,the constitutive equation and microstructure model of titanium alloy TC4 were established through the thermal compression experiment,and the obtained model was imported into the deform-3d finite element analysis software to simulate the reverse extrusion and thinning drawing process of titanium alloy TC4.Thermecmast-z thermal simulation test machine was used to conduct the thermal compression experiment with the temperature of 850??1050?and the strain rate of0.01?1s^-1.The effects of temperature and strain rate on the deformation behavior of titanium alloy TC4 were studied.The constitutive equation and the dynamic recrystallization model of TC4 in the two phase region and the single phase region are constructed according to the experimental stress-strain curves.The constitutive equation and dynamic recrystallization model of TC4 were imported into the software subroutine of DEFORM3D by using the programming language,and the simulation system of TC4 was established.16 groups of reverse extrusion processes with temperatures of 900?,950?,1000?and 1050?and extrusion speeds of 5mm/s,50mm/s,100mm/s and 150mm/s were simulated respectively.The displacement load,percentage of dynamic recrystallization and grain size under different deformation conditions were coMPared and analyzed.The optimum process parameters obtained were deformation temperature of 1000?and extrusion speed of 100mm/s.According to the existing laboratory conditions,a titanium alloy TC4 extrusion experiment die was designed,and a back extrusion experiment with a temperature of 1100°C and an extrusion speed of 5 mm/s and a process parameter of 0.72 thinning amount and a temperature of 1010°C were performed.In the thinning and deepening experiment at a depth of 5mm/s,the displacement load-load curve and TC4 cylindrical part of the extrusion were obtained,and the metallographic structure and grain size of each part of the test piece were observed.Co MParing the experimental and simulation results under the same deformation conditions,it is found that the two are basically consistent.