Experiment Study On Process Of Superplastic Forming/diffusion Bonding For Double-sheet Structure Of TA-15 Titanium Alloy

Superplastic forming/diffusion bonding is a pioneering technology in the field of modern aeronautics and astronautics,it improves the material utilization,enhances the structural reliability,satisfies the request of light weight and integrated production.As an advanced and lightweight manufacturing technology,the process of SPF/DB,which can save costs and form a high-quality overall structural parts with its high efficiency and free forming.In this paper,TA15 titanium alloy was used as the research object to study the SPF/DB process with the complex reinforcing rib structure.Firstly,this paper studied on the superplastic deformation behavior of TA15 titanium alloy with superplastic tensile test,and investigated the situation under different temperature and strain rate of TA15 titanium alloy with constant strain rate tensile method.Secondly,this paper simulated the forming of double-sheet structure by the software of MSC.MARC,and got the thickness distribution of structure and optimized pressure-time curve.According to the simulation results and optimized pressure-time curve,the forming of the double-sheet structure was accomplished successfully in a hot forming/superplastic forming machine.Finally,this paper focused on the quality analysis and metallographic analysis in the key positions of forming part.The tests results indicated that TA15 titanium alloy possesses the best superplasticity under the condition of 930? and strain rate of 5.25×10-4s-1,with ductility of 1060%,and m=0.56,K=810.The forming part of the formed double-sheet structure has a good forming quality,the interface of diffusion bonding disappears and attains the metallurgical connection with no obvious defects.