Research On Numerical Simulation Of Stress And Deformation Of Ti48AL2Cr2Nb Alloy Castings

With the rapid development of the aerospace, aviation technology and automobileindustry, the materials with heat-resistant,high-strength and lightweight propertiesshould be better and better. TiAl based alloy is a new type of lightweight,heat-resistant and high-strength material, so it has been widespread concerned. But italso brings some disadvantages, such as the low elongation, being difficult to producecomplex parts, especially thin-walled parts, prone to surface deformation and cracksresulting from the powerful internal stress.In this paper, numerical simulation is being used with the commercial castingsimulation software ProCAST in order to study the influence of casting filling,solidification and cooling process when manufacturing the Ti48Al2Cr2Nb alloy. Twofactors which are temperature and stress are studied and the deformation and defectsresults are obtained for analyzing the parameters. Physical parameters of the alloycasting are ensured by researching the predecessors work, experimental test andnumerical evaluation which is helpful to establish the relatively complete materialdatabase and stress database. The interface database and the boundary conditiondatabase are built according to the heat transfer coefficient,boundary conditions andother factors.By the simulation experiment of grid structure casting, the regularity of the stressand deformation for the casting is obtained due to the pouring temperature of theliquid metal, the preheating temperature of shell, and the rotation speed of centrifugalcasting. The experimental results show that the effective stress of internal casting, andthe trend of making cracks will be reduced though an appropriate pouring temperatureof the liquid metal (superheat150℃), high preheat temperature of the shell, lowrotation speed of centrifugal casting. Among these three factors, the pouringtemperature of the liquid metal is the most important, followed by the preheatingtemperature of shell and the rotation speed of centrifugal casting is the minimuminfluence.For the casting process of the engine blades, analyze the different gating systemstructures, different casting process parameters on the impact of stress anddeformation, to find the optimal process solution. It’s the best way of adopting bottomgating system and gravity casting method. And the optimal process solution is that thepouring temperature of the liquid metal is1650℃, preheating temperature of shell is300℃and the pouring time is about2s.