The properties of Al-Li alloys have been evaluated against the needs of the aircraft industry, and compared with the properties of the 2024-T3 alloy used for aircraft parts today.
Further studies need to be done on the mechanics and physics of fatigue crack growth, to quantitatively account for peak load interactions.
New aluminium-litium alloys offer aircraft manufacturers considerable weight saving potential without extensive conversion of their manufacturing facilities.
At present the main material used for civil aircraft structures is the conventional alloy 2024 T3 because of its excellent damage tolerant behaviour. Al-Li alloys becoming available do not cover the whole range of properties required by the aircraft industry in respect of damage tolerance.
A priority of the programme is to identify the weak points of the existing materials and to define procedures for improvements.
A further increase in attractiveness and cost-efficiency for future use of the material will be possible when a naturally aged alloy becomes available instead of the artificially aged alloy.
Another priority is the understanding and evaluation of specific behaviours of the now available alloys which are specific to Al-Li and mainly unkwon today. Special items such as corrosion, fracture toughness, flight simulation and component tests have to be solved.
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