P. Lequeu, Alcan Rhenalu, Issoire, France; J. C. Ehrstrom, C. Hantrais, Alcan, Voreppe, France; I. Bordesoules, Alcan CRV, Voreppe, France
Alcan Aerospace have been very active in the recent past in developing low density Al-Li 3rd generation of alloys, in a collaborative effort with airframers. AA2050 is one such alloy which has received commercial interest for its behaviour in the medium gauge range, where it outperforms reference alloys like 2024 or 2027, with significantly higher static, F&DT and corrosion performance, in addition to lower density and higher modulus. For higher gauges, AA2050 also offers an interesting low density alternative to 7050.
One of the challenges to the extensive use of Al-Li alloys by airframers has traditionally been the extra cost per kilo saved offered by such alloys. This is the reason why work has been performed to decrease their buy-to-fly ratio, among other cost reduction activities. One way of improving this buy-to-fly ratio consists in replacing integrally machined items by assembled parts, each being adjusted to the local thickness needs. When developing such concepts, one has to consider using as much as practical a low cost assembly technique, like what is offered by friction stir welding instead of standard riveting.
In an attempt to answer such a cost challenge, Alcan Aerospace have performed friction stir welding trials of 17m long structural parts made of 2050 alloy, in collaboration with the Institut de Soudure of Metz, France.
The presentation will provide the details of the implementation of such project, which proved to be very successful in all aspects, and which is believed to be a world first as far as welding duration is concerned. Extensive static & F&DT properties within the weld and in the heat-affected-zone will also be reported and compared to those of the base-metal.
Summary: Presentation is describing a full scale 17m long friction stir weld trial performed in collaboration with the Institut de Soudure of Metz, France, on Al-Li medium gauge 2050 plates. Details of the trial configuration will be provided, as well as results of the extensive static and F&DT characterization of the weld zone.
