# US 11,111,562 B2 · Aluminum-copper-lithium alloy with improved mechanical strength and toughness

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- Number: US 11,111,562 B2
- Document ID: US11111562B2
- Status: Granted
- Kind: B2
- Application number: 12/820,495
- Filed: 2010-06-22
- Published: 2011-02-10
- Granted: 2021-09-07
- Earliest claimed: 2009-06-25
- Assignees: Constellium Issoire
- Applicants: Timothy Warner; Christophe Sigli; Cedric Gasqueres; Armelle Danielou
- Inventors: Timothy Warner; Christophe Sigli; Cedric Gasqueres; Armelle Danielou
- Web page: https://patentgrep.com/patent/US11111562B2

## CPC

- C22C 21/00: Alloys based on aluminium
- C22C 21/16: with magnesium
- C22F 1/04: of aluminium or alloys based thereon
- C22F 1/057: of alloys with copper as the next major constituent
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- C22F: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass, C23F17/00)

## Abstract

The invention relates to a wrought product such as an extruded, rolled and/or forged aluminum alloy-based product, comprising, in weight %: Cu: 3.0-3.9; Li: 0.8-1.3; Mg: 0.6-1.0; Zr: 0.05-0.18; Ag: 0.0-0.5; Mn: 0.0-0.5; Fe+Si≤0.20; Zn≤0.15; at least one element from among: Ti: 0.01-0.15; Sc: 0.05-0.3; Cr: 0.05-0.3; Hf: 0.05-0.5; other elements ≤0.05 each and ≤0.15 total, remainder aluminum. The invention also relates to the process for producing said product. The products according to the invention are particularly useful in the production of thick aluminum products intended for producing structural elements in the aeronautical industry.

## Claims

### Claim 1

An aluminum-based wrought product that is rolled and has a thickness from 10-130 mm, said product comprising, in weight %:
Cu: 3.5-3.7;
Li: 0.9-1.2;
Mg: 0.6-0.8;
Zr: 0.05-0.18;
Ag: 0.0-0.5;
Mn: 0.0-0.5;
Fe+Si≤0.20;
Zn≤0.15;
at least one element selected from the group consisting of: Ti: 0.01-0.15; Sc: 0.05-0.3; Cr: 0.05-0.3; Hf: 0.05-0.5;
other elements ≤0.05 each and ≤0.15 total, remainder aluminum;
wherein the composition is selected so as to obtain a density that is not more than 2.71 g/cm3,
which in a rolled state, solution treated, quenched and aged so as to obtain a near-peak yield strength, has, at half-thickness, at least one of the following pairs of properties:
for thicknesses from 10 to <30 mm: a yield strength Rp0.2(L)≥525 MPa and a toughness K1C (L−T)≥45 MPa√m,
for thicknesses of 30 to <60 mm: a yield strength Rp0.2(L)≥525 MPa and a toughness K1C (L−T)≥43 MPa√m,
for thicknesses of 60 to <100 mm: a yield strength Rp0.2(L)≥520 MPa and a toughness K1C (L−T)≥40 MPa√m, or
for thicknesses of 100 to 130 mm, at half-thickness, a yield strength Rp0.2(L)≥510 MPa and a toughness K1C (L−T)≥37 MPa√m,
and wherein at least two properties of the product do not change more than 5% after thermal exposure of 1000 hours at 85° C., the at least two properties selected from the group consisting of: tensile yield strength Rp0.2 (L), ultimate tensile stress UTS (Rm L), and an elongation at rupture A % (L).

### Claim 2 (depends on 1)

A product according to claim 1, wherein the magnesium content is from 0.65 to 0.8% by weight.

### Claim 3 (depends on 1)

A product according to claim 1, wherein the manganese content is from 0.2 to 0.4% by weight.

### Claim 4 (depends on 1)

A product according to claim 1, wherein the silver content is from 0.15 to 0.35% by weight.

### Claim 5 (depends on 1)

A product according to claim 1, wherein the iron and silicon contents are each at most 0.08% by weight and/or in wherein the zinc content is ≤0.05% by weight.

### Claim 6 (depends on 1)

A product according to claim 1, wherein the thickness is equal to at least 30 mm.

### Claim 7 (depends on 1)

A structural element comprising a product according to claim 1.

### Claim 8 (depends on 7)

An aeronautical construction comprising a structural element of claim 7.

### Claim 9 (depends on 8)

An aeronautical construction according to claim 8 in which the structural element is an underwing or upper wing element of which skin and/or stringers can be obtained from the same starting product, a spar and/or a rib.

### Claim 10 (depends on 1)

A product according to claim 1, which in a rolled state, solution treated, quenched and aged so as to obtain a near-peak yield strength, has, at half-thickness, at least one of the following pairs of properties:
for thicknesses from 10 to <30 mm: a yield strength Rp0.2(L)≥545 MPa and a toughness K1C (L−T)≥45 MPa√m,
for thicknesses of 30 to <60 mm: a yield strength Rp0.2(L)≥545 MPa and a toughness K1C (L−T)≥43 MPa√m,
for thicknesses of 60 to <100 mm: a yield strength Rp0.2(L)≥535 MPa and a toughness K1C (L−T)≥40 MPa√m, or
for thicknesses of 100 to 130 mm, at half-thickness, a yield strength Rp0.2(L)≥525 MPa and a toughness K1C (L−T)≥37 MPa√m.