Form This specification covers an aluminum alloy in the form of castings. Application These castings have been used typically for durability and damage tolerance structural aircraft components (see 8.2) requiring fatigue resistance and fracture toughness@ but usage is not limited to such applications. Safety - Hazardous Materials While the material@ methods@ applications@ and processes described or referenced in this specification may involve the use of hazardous materials@ this specification does not address the hazards which may be involved in such use. It is the sole responsibility of the user to ensure familiarity with the safe and proper use of any hazardous materials and to take necessary precautionary measures to ensure the health and safety of all personnel involved.