New Aluminum-Based Thick Gauge Products for Increased Fuel Efficiency and Reduced Maintenance Cost in Next-Generation Aircraft

As commercial and military aircraft operators continue to be under pressure to reduce operating costs, aircraft manufacturers are responding by significantly increasing fuel efficiency of their new airplanes, mainly through new engine designs and aerodynamic improvements but also through lighter structural components. The latter is made possible in part through the extensive use of advanced aluminum products (e.g. 3^rdgeneration Al-Li alloys). Important considerations such as raw material cost, one time and recurring manufacturing costs, three dimensional properties, long term in-service performance and recyclability can be determining factors in the selection of aluminum alloys over other metallic or composite materials.

A new generation of “thick” aluminum alloy products is being developed by Alcoa, specifically targeted at internal structural components such as ribs, spars, thick frames, landing gear components, etc. The performance of these new products along with their development and commercialization status will be presented. Following extensive trials and product testing, a new 7xxx series thick plate alloy registered as 7065 is now being commercialized in both T7651 and T7451 tempers as a high strength replacement to incumbent 7050-T7451 plate from 1 to 6in. Temper registrations, AMS specifications and MMPDS approval are expected in 2014. Separately, Al-Li 2060 die forgings have also undergone a number of trials, offering 4% density saving and a significant strength improvement over incumbent 7050 forgings; this program achieved a milestone in 2013 with the derivation of S-basis allowables for section thicknesses ranging from 1 to 4in. Finally, a silver-free Al-Li alloy, registered as 2070, is a cost effective alternative to Al-Li 2050 for plate and forging thicknesses from 1 to 5in that exhibits 1% lower density, similar or improved mechanical performance and best-in-class corrosion performance.