Recent Developments in SiC-fibre reinforced titanium shafts

Abstract

The main shaft of an aircraft’s engine transmits extremely high torques at elevated temperatures. Therefore, high strength materials with low densities are required. The torque capability of these shafts can be considerably enhanced by the application of composite materials such as silicon carbide fibre reinforced titanium alloys. Titanium matrix composites (TMCs) offer high specific strength and high specific stiffness at temperatures up to 550°C depending on the matrix alloy. Engine shafts require higher torsion strength in one direction than in the other one. To meet these requirements specific designed tubular samples have been manufactured and tested. Considering the characteristic behaviour of SiC fibre reinforced titanium alloys a unidirectional angle ply lay-up promises optimum properties. To produce tubular samples with this special lay-up a special technique has been developed which requires neither costly machines nor time consuming processes. Results have shown a maximum torque of the reinforced shafts nearly twice as high as unreinforced titanium shafts. The manufacturing process, experimental results and efforts to improve affordability will be presented. Not only efficiency of engines can be increased but also weight of other components in all sectors of the transportation industry can be reduced.