Numerical Simulation And Process Optimization On Sheathed Extrusion Process Of Ti40Burn Resistant Titanium Alloy

As the urgent needed key structure material in aircraft engine, Ti40alloy hasexcellent burn resistance, which burn with a far lower rate than other high temperatureapplying titanium alloy. But it also has some disadvantages such as high deformationresistance, poor processing plasticity, narrow window of thermal process andextremely poor performance of hot work has limited the applying of this alloy. In thisthesis, as the research object, the process of sheathed extrusion has been numericallysimulated, the simulation results can be used to provide theory and technique directionto actual production of Ti40alloy.In this research, the regularity for change of temperature of Ti40blank and thetemperature of sheath before extrusion have been studied, and the effects oftemperature, extrusion rate, extrusion ratio, structure of model and fraction conditionson sheathed extrusion process have been got through studying temperature field,equivalent stress field, equivalent strain field and deformation force, then theparameters of sheathed extrusion have been optimized. The research results shows thatthe temperature of Ti40blank have not fallen obviously at different deformationconditions; the parameters in extrusion process, model structure and fractionconditions have significant influences on sheath extrusion process, which indicates thata proper processing condition can be obtained in order to lessen hardness of chillinglayer and deformation force, homogenize the flow of metal, finally get products hasmore precise shape and size.According to the simulation results, the optimal process condition for sheathextrusion of Ti40is that extrusion temperature in1150℃, deformation rate at0.5mm/s,die preheating temperature in300℃, and the αopt=50°+55°.