Materials Investigations and Process Improvement for a more Sustainable and Robust Leading Edge

Leading edges are an important part of an aircraft wing: They experience various mechanical (static, fatigue, bird strike) and thermal (temperature due to anti-icing) conditions. Leading edges are normally made with aluminum alloys. For business jets, the leading edges also have an aesthetic function, they are polished and must keep a brilliant surface aspect during their lifetime. The materials are subjected to erosion, to corrosion on the ground and during flight. Therefore, the leading edges need a special protection or a good resistance to corrosion.

Historically, Dassault-Aviation uses Alclad 2024 T4 aluminum alloy to manufacture the business jet leading edges. The cladding is a pure aluminum layer that protects the 2024 T4 alloy against corrosion. The pure aluminum has low yield stress properties and parts are easily damaged during manufacturing, handling and flight. The polishing of the leading edge during the aircraft lifetime leads to thinning and eventual total stripping of the clad layer. The leading edge is then fully bare without any protection against corrosion and has to be replaced.

For these reasons, Dassault-Aviation has investigated bare aluminum alloys with mechanical, thermal, corrosion and aesthetic properties to meet its requirements for leading edges. Aluminum alloys with magnesium and silicon such as 6056, present interesting alternatives to 2024. In this study, static, fatigue, damage tolerance and corrosion tests have been conducted on 6056 T78. The impact of thermal aging on the static mechanical properties of the 6056 T78 has also been evaluated. 6056 T78 properties will be compared with those of the Alclad 2024 T4 aluminum alloy baseline.