Aluminum-copper-lithium products

Patent metadata

Field	Value
Publication number	US-10190200-B2
Application number	US-201313733720-A
Country	US
Kind code	B2
Filing date	Jan 3, 2013
Priority date	Nov 14, 2008
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

Abstract

The present invention relates to extruded, rolled and/or forged products. Also provided are methods of making such products based on aluminum alloy wherein a liquid metal bath is prepared comprising 2.0 to 3.5% by weight of Cu, 1.4 to 1.8% by weight of Li, 0.1 to 0.5% by weight of Ag, 0.1 to 1.0% by weight of Mg, 0.05 to 0.18% by weight of Zr, 0.2 to 0.6% by weight of Mn and at least one element selected from Cr, Sc, Hf and Ti, the quantity of said element selected, being 0.05 to 0.3% by weight for Cr and for Sc, 0.05 to 0.5% by weight for Hf and 0.01 to 0.15% by weight for Ti, the remainder being aluminum and inevitable impurities. The products and methods of the present invention offer an advantageous compromise between static mechanical strength and damage tolerance and are useful in aeronautical design.

First claim

The invention claimed is:

1. A method of manufacturing an extruded product based on an aluminum alloy, said method comprising:
a) preparing a liquid metal bath consisting essentially of 2.72 to 3.1% by weight of Cu, 1.59 to 1.8% by weight of Li, 0.1 to 0.5% by weight of Ag, 0.1 to 1.0% by weight of Mg, 0.05 to 0.18% by weight of Zr, 0.2 to 0.6% by weight of Mn, and at least one element selected from Cr, Sc, Hf and Ti, the quantity of said element, if included, being 0.05 to 0.3% by weight for Cr and for Sc, 0.05 to 0.5% by weight for Hf or 0.01 to 0.15% by weight for Ti,
remainder aluminum and inevitable impurities;
b) casting an unwrought shape from said liquid metal bath;
c) homogenizing said unwrought shape at a temperature from 515° C. to 525° C. such that the equivalent time for homogenization

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is from 5 to 20 hours, where T (in Kelvin) is the instantaneous treatment temperature, which varies with the time t (in hours), and T ref is a reference temperature set at 793 K;
d) hot working and optionally cold working said unwrought shape into an extruded product;
e) subjecting the product to a solution treatment and quenching;
f) stretching said product with a permanent set of 1 to 5%; and
g) artificially aging said product by heating at 140 to 170° C. for 5 to 70 hours such that said product has a yield strength measured at 0.2% elongation in the L-direction of at least 517 MPa.

2. The method according claim 1 , wherein the silver content of said liquid metal bath is from 0.15 to 0.35% by weight.

3. The method according to claim 1 wherein the magnesium content of said liquid metal bath is less than 0.4% by weight.

4. The method according to claim 1 wherein the manganese of said liquid metal bath is not more than 0.35% by weight.

5. The method according to claim 1 wherein said inevitable impurities comprise iron and silicon, said impurities having a content less than 0.08% by weight and 0.06% by weight for iron and silicon, respectively, the other impurities having a content less than 0.05% by weight each and 0.15% by weight in total.

6. The method according to claim 1 wherein said equivalent time for homogenization is between 6 and 15 hours.

7. The method according to claim 1 wherein the homogenization temperature is about 520° C. and the treatment time is from 8 to 20 hours.

8. The method according to claim 1 wherein said artificial aging is carried out by heating at 148 to 155° C. for 10 to 40 hours.

9. The method according to claim 1 wherein the extruded aluminum alloy product has a density of less than 2.67 g/cm 3 .

10. The method according to claim 1 wherein the extruded aluminum alloy product has a thickness of at least one elementary rectangle of greater than 8 mm.

11. The method according to claim 10 wherein the extruded aluminum alloy product has a thickness of at least one elementary rectangle of greater than 12 mm.

12. The method according to claim 10 wherein the extruded aluminum alloy product has a thickness of at least one elementary rectangle of greater than 15 mm.

13. The method according to claim 1 wherein the extruded aluminum alloy product has a thickness of at least one elementary rectangle of between 1 mm and 8 mm.

14. The method according to claim 1 wherein the thickness of the extruded product is at least 10 mm.

15. The method according to claim 1 wherein the extruded aluminum alloy product has a toughness thereof KQ(L-T), in the L-T direction is at least 23.7 MPa.

16. The method according to claim 5 , wherein said other impurities comprise zinc.

Assignees

• Constellium France
• Constellium Issoire

Inventors

• Heymes Fabrice
• Eberl Frank
• Pouget Gaelle

Classifications

• C22C21/16

  with magnesium · CPC title

• C22C21/00

  Alloys based on aluminium · CPC title

• C22F1/057 Primary

  of alloys with copper as the next major constituent · CPC title

• C22F1/04

  of aluminium or alloys based thereon · CPC title