AlMgSc alloys - a novel approach for various aircraft applications

The high pressure on the aircraft manufacturers from the airline customers with regard to environmental friendliness (e.g. fuel efficiency) and operation and maintenance costs resulted in the last years in the development of new highly advanced and lightweight aluminium alloys in order to compete against fiber reinforced composites or other material concepts.

Compared to 2x24 type alloys which are being used since decades for fuselage, flap and slat applications the Sc containing 5xxx alloys provide advantages in terms of density and allow for new cost efficient manufacturing techniques at the customer for affordable structures.

In this paper the status of the advanced AlMgSc alloy AA5028 developed by Aleris will be presented. AA5028 offers good damage tolerance properties, a very low density (5% lower compared to 2024) and excellent corrosion resistance (no cladding required).

Due to the high thermal stability achieved via Sc and Zr additions AA5028 allows for both established and advanced manufacturing techniques such as welding and relaxation forming. Latest results on demonstrator manufacturing trials will give an insight into the unique new manufacturing possibilities offered by this type of alloys.

Also in case of short term drop-in solutions for derivative aircrafts AlMgSc alloys can be considered as a very promising candidate since the aircraft manufacturer can process 2D shaped AA5028 sheet applications according to the standard 2024 production route without any need for further investments while profiting from their advantages.