Aluminum magnesium lithium alloy with improved fracture toughness

Inactive Publication Date: 2012-11-22
CONSTELLIUM ISSOIRE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Benefits of technology

[0041]subjecting the product to artificial ag

Problems solved by technology

These alloys did not solve certain problems and in particular their performance in terms of damage tolerance has prevented them from being used significantly in commercial aviation.
It should also be noted that the manufacture of wrought products from these alloys has remained difficult and that the rejection rate is too high.

Method used

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  • Aluminum magnesium lithium alloy with improved fracture toughness
  • Aluminum magnesium lithium alloy with improved fracture toughness
  • Aluminum magnesium lithium alloy with improved fracture toughness

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0085]In this example, several Al—Mg—Li alloy plates, the composition of which is given in table 1, were cast. Alloy D has a composition according to the invention; alloys A to C are reference alloys.

TABLE 1Composition as a percentage by weight and densityof the Al—Mg—Li alloys usedNaAlloyAgLiSiFeCuTiMnMgZnZr(ppm)ScA0.11.80.040.040.170.020.134.60.460.0790.08B0.11.70.040.040.070.020.134.90.480.138C0.11.70.040.040.170.020.154.80.440.1211D0.11.40.050.040.180.020.154.50.124

[0086]The plates were heated and hot-rolled to a thickness of approximately 4 mm. Cold-rolling tests to thickness 2 mm were carried out after heat treatment made up of two successive steps of one hour at 340° C. followed by 1 hour at 400° C. Only the alloy sheets according to the invention could be cold-rolled successfully to the final thickness, reference alloy sheets having broken at thickness 2.6 mm After hot and possibly cold rolling, the sheets underwent solution heat-treatment at 480° C. for 20 min, this treatme...

example 2

[0096]In this example, small ingots were cast to evaluate hot ductility and intergranular corrosion properties of different alloys. The size of the ingot after machining was in mm 255×180×28.

[0097]The composition of the alloys is provided in Table 7.

TABLE 7Composition as a percentage by weight and densityof the Al—Mg—Li alloys usedAlloyAgLiSiFeCuTiMnMgZnZrCrScE—1.40.030.03—0.020.404.5—0.110.18—F—1.40.030.03—0.020.164.4—0.120.19—G—1.40.030.03—0.020.174.4—0.11——H—1.10.030.03—0.020.164.5—0.12——I—1.40.030.03—0.020.174.50.60.12——

[0098]Hot ductility was evaluated on tests samples machined from the small ingots after homogenization of 12 h at 505° C. The hot ductility test was carried out with a servo hydraulic instrument provided by Servotest Testing Systems Ltd on specific test samples having a thickness of 20 mm and at a deformation rate of 1 s−1. The test consists in the compression of a sample containing two holes. Due to the compression,

[0099]the material between the two holes expand...

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Abstract

Wrought product made of aluminum alloy composed as follows, as a percentage by weight Mg: 4.0-5.0; Li: 1.0-1.6; Zr: 0.05-0.15; Ti: 0.01-0.15; Fe: 0.02-0.2; Si: 0.02-0.2; Mn: ≦0.5; Cr≦0.5; Ag: ≦0.5; Cu≦0.5; Zn≦0.5; Sc≦0.01; other elements <0.05; the rest aluminum.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]This application claims priority to French Application No. 11 / 01555, filed May 20, 2011, and U.S. Provisional Application No. 61 / 488,196, filed May 20, 2011, the content of both of which are incorporated herein by reference in their entireties.BACKGROUND[0002]1. Field of the Invention[0003]The invention relates to aluminum-magnesium-lithium alloy products, and more particularly such products, their manufacturing processes and use, designed in particular for aircraft and aerospace construction.[0004]2. Description of Related Art[0005]Rolled products made of aluminum alloy are developed to produce parts of high strength designed in particular for the aircraft and aerospace industry.[0006]Aluminum alloys containing lithium (AlLi) are of great interest in this respect, because lithium can reduce the density of aluminum by 3% and increase the modulus of elasticity by 6% for each percent of added lithium weight. For these alloys to be selected f...

Claims

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Application Information

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IPC IPC(8): C22C21/08C22F1/047
CPCC22C21/06C22C21/00C22F1/047
InventorBES, BERNARDEBERL, FRANK
OwnerCONSTELLIUM ISSOIRE