Form This specification covers an aluminum alloy in the form of sheet 0.040 to 0.249 inches (1.02 to 6.32 mm)@ inclusive@ in thickness (see 8.5). Application This product has been used typically for structural applications requiring sheet with high strength and resistance to exfoliation-corrosion@ moderate fatigue strength@ and high fracture-toughness@ but usage is not limited to such applications.