The cost of corrosion for DoD has approached $20B per year. Naval aviation costs are about $5.4 billion/yr for corrosion related maintenance of aircraft and ships. Light-weight, high strength, aluminum alloys are used extensively throughout Navy aircraft, but require large repair and maintenance cost for damage due to corrosion. High strength alloys such as 7075 or 2024 are often clad with more anodic layers hot-roll bonded to the surfaces of the plate. The cladding serves as a barrier but also provides cathodic protection to the plate if the clad layer is penetrated. Clad products have limitations on the combination of alloys that can be bonded, and concerns over the integrity of the alloy bond interface. Cladding alloys are typically softer than the core material and undergo much more extensive plastic deformation during roll-bonding, which, along with properly prepared surfaces, are important factors in obtaining a bond which is free of voids or large oxide inclusions. The technical approach of this project is to develop the alloy technology for the use of the Novelis Fusion™ method of dual alloy casting and apply it to high strength and corrosion resistant, multilayer aluminum for aircraft applications.
Keywords: Corrosion Resistance, Aircraft Aluminum Alloys, 7075, Direct Chill Casting, Cathodic Protection
