Superplastic forming with diffusion bonding of titanium alloys

Abstract

The ability of materials to display extensive plastic deformation at elevated temperature before permanent deformation without necking is known as super plasticity. The optimization of superplastic forming can be evaluated by application of gas pressure at elevated temperatures using hot superplastic forming set up. The diffusion bonding process involves keeping together the required titanium alloy sheets or titanium alloy with any other metal with the help of load at elevated temperatures and in an inert environment preferably in vacuum for the bonding process to complete. This method is used to eliminate many bonding defects such as distortions and cracking which can occur in conventional joining methods such as welding and brazing or riveting. The resulting micro structure at the interface can be evaluated using scanning electron microscope (SEM) photography and also the bond strength can be determined using micro hardness tester. Titanium based alloys are super- plastic in nature at elevated temperatures, and they also display exceptional mechanical properties such as a great strength to weight ratio, good fatigue life good corrosion resistance, high torsional rigidity and excellent bio compatibility. The components bonded using both super plasticity and diffusion bonding possesses high tensile strength which is makes it reliable for aerospace applications.