Low-density aluminum-copper-lithium alloy products

Abstract

The invention relates to a product made of an aluminium-based alloy comprising, by wt. %, Cu: 2.4-3.2; Li: 1.6-2.3; Mg: 0.3-0.9; Mn: 0.2-0.6; Zr: 0.12-0.18; such that Zr≥−0.06*Li+0.242; Zn:<1.0; Ag:<0.15; Fe+Si≤0.20; optionally, at least one element selected from Ti, Sc, Cr, Hf and V, the content of the element, if selected, being: Ti: 0.01-0.1; Sc: 0.01-0.15; Cr: 0.01-0.3; Hf: 0.01-0.5; V: 0.01-0.3; other elements ≤0.05 each and ≤0.15 in total; the remainder being aluminium. The invention also relates to a method for manufacturing an as-cast aluminum alloy product according to the invention, comprising the following steps: preparing a liquid metal bath; casting an as-cast shape from said liquid metal bath; and solidifying the as-cast shape into a billet, a rolling plate or a forging blank; characterised in that the casting is performed without adding any grain refiner, or by adding a refiner comprising (i) Ti and (ii) B or C, such that the content of B from the refiner is less than 45 ppm, and that of C is less than 6 ppm, and/or characterised in that the casting is carried out, for an as-cast shape of thickness E or with a diameter D greater than 150 mm, at a casting rate v (mm/min) greater than 30 for a plate-type as-cast shape or 9000/D for a billet-type as-cast shape.

1 . A method for manufacturing a product made of aluminum alloy comprising:
 a) producing a bath of liquid metal;   b) casting an unwrought product from said bath of liquid metal;   c) solidifying the unwrought product into a billet;   wherein the casting is carried out without addition of a grain refiner or adding a refiner comprising (i) Ti and (ii) B or C, such that the concentration of B coming from a refining agent is less than 45 ppm, and the concentration of C is less than 6 ppm,   wherein the product after step c) is an as-cast product;   d) homogenizing the billet;   e) extruding the billet into an extruded product;   f) solution heat treatment and quenching said extruded product;   g) stretching in a controlled manner of said extruded product with a permanent set of 1 to 15%;   h) aging said extruded product by heating to 140 to 170° C. for 5 to 70 hours,   wherein after h), the product is a worked product.   
     
     
         2 . A structural element incorporating at least one product obtained by the method according to  claim 1 . 
     
     
         3 . The structural element according to  claim 2 , used for manufacturing an airplane-wing lower-surface or upper-surface elements, optionally stiffeners, spars and/or ribs, or one or more fuselage elements optionally stiffeners or frames, or elements of inner structure optionally floor beams or seat rails. 
     
     
         4 . The method according to  claim 1 , wherein the casting is carried out without addition of a grain refiner or adding a refiner comprising (i) Ti and (ii) B or C, such that the concentration of B coming from a refining agent is less than 20 ppm, and the concentration of C is less than 3 ppm. 
     
     
         5 . The method according to  claim 1 , wherein the casting is carried out without addition of a grain refiner or adding a refiner comprising (i) Ti and (ii) B or C, such that the concentration of B coming from a refining agent is less than 10 ppm, and the concentration of C is less than 2 ppm.