High Strength Aluminum Alloys for Cryogenic Applications

A super-high strength cast and wrought aluminum alloy with specific strengths exceeding that of a Ti-5Al-2.5Sn alloy and tensile ductility of about 10% or higher, both at room and cryogenic temperatures, has been developed by modifying the composition and heat treatment of a 7XXX series alloy. This aluminum alloy is a potential candidate to replace the more expensive titanium alloy, which is currently used in some cryogenic rocket engine applications. Microstructure and tensile properties of the aluminum alloy after casting, extrusion and forging and after different heat treatment are presented and the effect of processing parameters on the properties is discussed.