What is the primary type of aluminum used on naval aircraft?

• A. Nonclad aluminum alloys
• B. Alclad aluminum alloys
• C. Cast aluminum alloys
• D. Wrought aluminum alloys

Answer: (A)

The main type of aluminum used on naval aircraft is nonclad aluminum alloys. This category refers to the base alloys without the protective outer cladding layer. They are favored for most structural components because they offer high strength-to-weight, good formability, and lower cost, which suits the bulk of the airframe manufacturing and maintenance needs. Corrosion protection in naval environments is then achieved through protective coatings, primers, sealants, and regular maintenance rather than relying on a clad surface.

Alclad alloys, which have a thin layer of pure aluminum on the outside, are used on exterior skins or surfaces that face salt spray more directly, to improve corrosion resistance where exposed. Cast aluminum alloys are chosen for specific components that are easier to cast and do not require the highest strength, and wrought aluminum alloys include both clad and nonclad forms. But for the majority of the airframe, nonclad alloys are the primary material.