Reserch On The Microstructure And Properties Of TC4 Alloy Under Different Deformation Conditions

TC4 titanium alloy has many advantages,such as low density,high strength,good corrosion resistance,good mechanical properties,good plasticity,weldability and so on,It is more and more popular in the field of aviation and spaceflight.In this paper,TC4 titanium alloy has been studied in depth,under different conditions of deformation,deformation rate and deformation temperature.The isothermal compression experiment of TC4 alloy was carried out on Gleeble-1500 D thermal simulator.Using the modified Arrhenius model,which was a hyperbolic sine function including the material parameter function of ?(?)?n(?)?Q(?)and A(?),was used to describe the hot compression constitutive equations of the alloy.The work hardening rate method is adopted based on the ?-? curve and cubic polynomial fitting method for solving inflection point,under the condition of different deformation was obtained the critical stress of dynamic recrystallization occurs,to establish the relationship between the critical stress and Z parameters,obtain the dynamic recrystallization critical stress equation,the alloy under different deformation conditions of dynamic recrystallization critical strain changes are very little.Draw the processing map of TC4 titanium alloy,by using the transmission electron microscope(TEM)?metallographic microscope and scanning electron microscope(SEM)observation of microstructure to demonstrate the effectiveness of processing map.The effects of different solid solution temperature and aging time on the microstructure and properties of TC4 titanium alloy were studied by means of heat treatment of TC4 titanium alloy.Tensile properties of TC4 titanium alloy were tested by MTS tensile testing machine.In order to verify the accuracy of the simulation data,to design a kind of unidirectional high temperature compression mold compressing process numerical simulation.The effects of different deformation conditions on the microstructure and properties of TC4 titanium alloy were studied.The results show that stress-strain diagrams can well reflect the stress of TC4 titanium alloy under different deformation conditions By the constitutive equation tocalculate the stress value and experimental value has high value of correlation coefficient(R2=0.9743).In the actual forging process,the microstructure and stress show that the same rule on the phase transformation instrument.By observing the microstructure under the deformation condition of900-950 ?,0.01-0.1s-1strain specimens are typical lamellar structures,have stable organization and high toughness,have high strength at high temperature,materials processing performance is best,having the highest forming quality.The comprehensive material processing performance is the best.