Aluminium-copper-lithium alloy sheets for producing aeroplane fuselages

Inactive Publication Date: 2016-03-03
CONSTELLIUM ISSOIRE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The invention is an aluminum-based alloy sheet that has specific properties and is suitable for use in aircraft fuselage panels. The sheet is made through a process that involves casting, homogenization, hot rolling and optionally cold rolling, solution heat treatment, quenching and aging. The composition of the sheet is controlled to yield a yield stress of between 395 and 435 MPa in the longitudinal direction. The technical effects of the invention are improved fatigue resistance, reduced weight and improved strength of aircraft fuselage panels.

Problems solved by technology

Thus, the state of the art knowledge is unable to predict which alloys and which thermomechanical treatments will allow the most advantageous properties to be attained for Kapp and for the level of the R-curve of wide width panels, as properties will influence the damage tolerance dimensioning.
Indeed, in some configurations the bending stresses on the fuselage around the axis of the wings become critical, notably for the upper part of the fuselage.

Method used

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  • Aluminium-copper-lithium alloy sheets for producing aeroplane fuselages
  • Aluminium-copper-lithium alloy sheets for producing aeroplane fuselages
  • Aluminium-copper-lithium alloy sheets for producing aeroplane fuselages

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0087]In this example, Al—Cu—Li alloy sheets were prepared.

[0088]Five slabs, the composition of which is given in Table 1, were cast. Compositions B, C, D and E are according to the invention.

TABLE 1Composition as a percentage by weightReferenceCuLiMgZrAgFeSiTiA3.20.730.680.140.260.030.040.03B3.00.700.640.170.270.020.030.03C3.00.730.350.150.270.020.030.03D2.70.750.580.140.280.030.020.03E2.90.730.450.140.290.040.020.03

[0089]The slabs were homogenized 12 hours at 505° C. The slabs were hot rolled to obtain sheets with a thickness of between 4.2 to 6.3 mm Certain sheets where then cold rolled to a thickness between 1.5 and 2.5 mm. The detail of sheets obtained and the aging conditions is given in Table 2.

TABLE 2detail of sheets obtained and aging conditionsThickness Thickness Aging after hotafter cold time at Referencerolling (mm)rolling (mm)155° C. (h)A#14.2—36A#24.41.536B#14.6—36B#24.41.536C#14.3—24C#24.41.524D#14.3—40D#26.32.540E#14.3—36E#26.32.536

[0090]After hot rolling and possibl...

example 2

[0100]In this example, the effect of the aging conditions was studied on the fracture toughness of Al—Cu—Li alloy sheets of composition according to the invention.

[0101]Following treatment identical to that of example 1, except for aging, sheets made of alloy E underwent aging for 20 h at 155° C. or for 25 h at 155° C.

[0102]The granular structure is not changed by these aging conditions. The test samples were mechanically tested to determine their static mechanical properties as well as their resistance to fatigue crack propagation. The yield stress under tension, the ultimate strength and elongation at rupture are given in Table 6.

TABLE 6Mechanical properties expressed in MPa (Rp0.2, Rm) or in percentage (A %)Rp0.2(TL) / Rp0.2(TL)Aging48 h durationRp0.2RmA % Rp0.2RmA % 155° C.ReferenceA155° C.(L)(L)(L)(TL)(TL)(TL)(%)E#120 h4224701339044016.590%E#220 h41145012.437444312E#125 h44248312.441545615.796%E#225 h43146611.139145511.7E#136 h45348712.542846415.999%E#236 h43346411.439545811.4

[01...

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Abstract

The invention concerns a sheet 0.5 to 8 mm thick made from aluminium alloy. The sheet can be obtained by a method comprising casting, homogenising, hot rolling and optionally cold rolling, solution heat treatment, quenching and tempering, the composition and the tempering being combined in such a way that the elasticity limit in the longitudinal direction Rp0.2(L) is between 395 and 435 MPa. A sheet according to the invention is particularly advantageous for producing aircraft fuselage panels.

Description

SCOPE OF THE INVENTION[0001]The invention relates to aluminum-copper-lithium alloy rolled products, and more particularly to such products, their manufacturing processes and use, intended notably for the field of aeronautical and aerospace construction.STATE OF THE ART[0002]Rolled products made of aluminum alloy are developed in order to produce fuselage components intended notably for the aeronautical and aerospace industry.[0003]Aluminum-copper-lithium alloys are particularly beneficial for the production of this type of product.[0004]U.S. Pat. No. 5,032,359 describes a vast family of aluminum-copper-lithium alloys in which the addition of magnesium and silver, in particular between 0.3 and 0.5 percent by weight, makes it possible to increase the mechanical strength.[0005]U.S. Pat. No. 5,455,003 describes a process for manufacturing Al—Cu—Li alloys that have improved mechanical strength and fracture toughness at cryogenic temperature, in particular owing to appropriate strain hard...

Claims

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Application Information

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IPC IPC(8): C22F1/057B22D21/00C22C21/14C22C21/16
CPCC22F1/057B22D21/007C22C21/14C22C21/16
InventorCHEVY, JULIETTEBES, BERNARDEBERL, FRANKEHRSTROM, JEAN-CHRISTOPHE
OwnerCONSTELLIUM ISSOIRE