Damage Tolerance Behaviour of Aluminium-Lithium Sheet Alloys.

摘要

Since 1984 the NLR has carried out an extensive evaluation of the damage tolerance properties of modern aluminum-lithium (Al-Li) alloys. The materials tested include damage tolerant tempers of the 2091 and 8090 alloy, and the high strength 2090 alloy. These have been compared with the conventional and widely used damage tolerant 2024-T3 alloy and the high strength 7075-T6 alloy. Qualification of Al-Li alloys for aerospace structures emphasizes the fracture and fatigue crack growth properties in the in-service inspectable damage tolerance regime. In the investigation the fracture toughnesses, crack resistances and fatigue crack growth properties of Al-Li and conventional sheet alloys have been determined and included in the report. The practical significance of the results is discussed, and the current status of Al-Li sheet alloys is indicated. Also, a survey is given of a comprehensive qualification program that includes other properties besides those related to damage tolerance.