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Innovative Aluminium filler Wires for Aircraft Structures

Periodic Reporting for period 2 - IAWAS (Innovative Aluminium filler Wires for Aircraft Structures)

Reporting period: 2020-04-01 to 2021-09-30

Innovative Al filler Wires for Aircraft Structure (IAWAS) addresses the lack of commercial Al filler wire available on the market for the Wire based deposition Additive Manufacturing (AM) and Laser Beam Welding (LBW) of the new Al-Li alloy parts. Moreover, WAAM (Wire + Arc Additive Manufacture) and LBW issues with the new Al-Li alloys, such as porosity, oxidation and loss of mechanical properties will be investigated.

The use of Al-Li alloys in the aerospace industry will lead to weight savings due to the fact that these alloys are characterized by their low density, excellent corrosion resistance, superior fatigue performance, high fracture toughness, and excellent static properties. The development of WAAM of Al-Li alloys will not only reduce the weight of the manufactured parts but also improve its buy to fly ratio. Indeed, this technology places raw material only where it is needed for part functionality, limiting the amount of chips and offcuts produced during machining operations. Typically, in the aerospace industry only 10% of the material purchased remain in the final product with 90% of the material being recycled (as a best-case scenario) and being sold as scrap for a low value. Concurrently, Laser Beam Welding (LBW) is considered as one the most promising routes for substituting mechanical joining, contributing to weight and cost savings in the aircraft industry. LBW provides high productivity, high weld quality, low distortion manufacturing flexibility and ease of automation.

IAWAS overall objectives are:
- Developing new wire compositions able to be used in the Laser Beam Welding (LBW) and Wire Arc Additive Manufacturing (WAAM) of the 3rd generations of Al-Cu-Li alloys.
- Implementing the new Al filler wires in the LBW and WAAM processes.
- Optimising the WAAM process and implementing post-treatments (surface and heat-treatments) in such a way as to obtain material properties in compliance with the requirements of the targeted product.
- Characterising the microstructure, mechanical properties and corrosion resistance of the optimised post-treated WAAM material in relation to the requirements of the targeted product.
- Manufacture by WAAM of two demonstrators representative of the targeted product with a previous combined structural and geometry analysis as well as a cost analysis.
- Evaluating the internal and external quality of the demonstrators
AA2395 and AA2196 filler wires were manufactured:
- AA2196 did not have the required quility to be tested in WAAM and LBW
- AA2395 has been used to perform WAAM and LBW tests

Thanks to this first tests and several bibliographical investigations D1.1 was issued with the new compositions to be cast and drawn. LBW and WAAM will need different alloys.

The composition to be used for next WAAM tests is already available at CU and is currently being tested. The new manufacturing route developed by SW and UAC allow SW to successfully drawn and shave the wire.
The project expect to develop two new filler wires, one for WAAM and one for LBW.
Besides, one demonstrator will be manufactured by WAAM and delivered to ECOTECH project.
First WAAM walls