Optimization Of Superplastic Isothermal Forging Process Of TC6 Titanium Alloy Based On Maximum M Value

TC6 is a kind of titanium alloy with two-phase structure,which has been widely used in aviation field.In this paper,the TC6 titanium alloy without refinement is taken as the research object,and the thermal deformation behavior of TC6 under different experimental parameters is studied by superplastic tensile test and superplastic isothermal forging test.The equivalent strain rate method based on the maximum m value is derived.A control program for applying equivalent strain rate to engineering forging is developed,and a method of controlling forging process by strain rate sensitivity index is proposed.At a temperature of 830~910 ?,The tensile test of TC6 titanium alloy without grain refinement has been carried out at constant strain rate method and maximum m method The experimental results show that the optimum deformation temperature range of TC6 rod titanium alloy is 850 ~870?,The stress strain rate sensitive region of TC6 titanium alloy is 2×10-4s-1~5×10-4s-1.At 850?,the elongation of the TC6 bar material is obtained by stretching the maximum m value of 900%.The equivalent strain rate under some deformation condition is derived by the maximum m method,By this method,the best strain rate at the current temperature can be obtained by an experiment,And can obtain optimum elongation.The equivalent strain rate based on the maximum m value can provide a reference for the performance testing of metal superplastic materials,which greatly improves the experiment efficiency is measured in the experiment.When the experimental temperature is 830?,850?,870?,890?,the equivalent strain rate of TC6 is 2.6×10-4s-1,3.0×10-4s-1,3.4×10-4s-1 and 3.3×10-4s-1.The elongation rate of 892% and 855% was obtained at the experimental temperature of 850 ? and 870 ? by equivalent strain rate superplastic tensile test.Then,the method of applying maximum m theory to engineering practice is put forward,and the program development of 400 T forging press is carried out.The program can realize data collection,analysis and archiving,equipment monitoring and real-time data curve generation.Finally,the forging test of TC6 titanium alloy by equivalent strain rate method was carried out,and the TC6 aero actuator was simulated by equivalent strain rate.Experiments and simulations show that the strain rate obtained by the equivalent strain rate method based on the maximum m value can balance the hardening and softening mechanisms in the TC6 deformation process.Therefore,the best plastic effect can be obtained.At an equivalent strain rate of TC6,the flow stress remains at very low levels and is well suited for the production of large titanium alloy forgings.