Advances in the Development of Plate Products for Lower Wing Applications

Al-Li-Cu-Mg alloy/products, with and without Ag additions provide substantial performance advantages over conventional 2xxx products.  For lower wing applications, the combination of specific ultimate tensile strength and plane stress fracture toughness is of particular importance and this is an area in which the Al-Li alloys can excel.  Corrosion resistance is an area that has received attention since it can impact inspection intervals.  In this presentation, the microstructures and properties of two new alloy/products aimed for lower wing applications,

2199-T86 and 2060-T8E86, will be reviewed and compared with conventional non-Li 2xxx products. The state of maturity in terms of temper registration, AMS and design allowables is examined in detail. It is concluded that the performance improvements of Al-Li alloys/products in addition to their lower density should enable significant weight savings in modern aircraft.