Alcan Rhenalu

Bernard Bés

Timothy Warner

Philippe Jarry

Christophe Sigli

Hervé Ribes

A low density aluminum based alloy useful in aircraft structure for fuselage sheet or light-gauge plate applications which has high strength, high fracture toughness and high corrosion resistance, comprising 2.7 to 3.4 weight percent Cu, 0.8 to 1.4 weight percent Li, 0.1 to 0.8 weight percent Ag, 0.2 to 0.6 weight percent Mg and a grain refiner such as Zr, Mn, Cr, Sc, Hf, Ti or a combination thereof, the amount of which being 0.05 to 0.13 wt. % for Zr, 0.1 to 0.8 wt. % for Mn, 0.05 to 0.3 wt. % for Cr and Sc, 0.05 to 0.5 wt. % for Hf and 0.05 to 0.15 wt. % for Ti. The amount of Cu and Li preferably corresponds to the formula Cu(wt. %)+5/3 Li(wt. %)&#x3c;5.2.

High fracture toughness aluminum-copper-lithium sheet or light-gauge plate suitable for use in a fuselage panel

Process for manufacturing aluminum alloy products, with high toughness and fatigue resistance comprising: (a) preparing an aluminum alloy bath, (b) adding a refining agent containing particles of AlTiC type phases into the bath, (c) casting an as-cast form such as an extrusion ingot, a forging ingot or a rolling ingot, (d) hot transforming the as-cast form, possibly after scalping, to form a blank or a product with final thickness, (e) optionally cold transforming the blank to a final thickness, (f) applying a solution heat treatment and quenching the product output from (d) or (e), followed by relaxation by controlled stretching with permanent elongation between 0.5 and 5%, and optionally annealing, wherein the quantity of refining agent is chosen such that the average casting grain size of the as-cast form is more than 500 &#x3bc;m. The present invention may be used, for example, to manufacture fuselage sheet or light-gauge plates made with 6056 alloy.

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Seyssins, France

Bernard Bés