CLAD 2XXX-SERIES AEROSPACE PRODUCT

Abstract

The invention relates to a rolled composite aerospace product comprising a 2XXX-series core layer and an Al—Mg alloy clad layer coupled to at least one surface of the 2XXX-series core layer, wherein the Al—Mg alloy is a 5XXX-series aluminium alloy comprising 0.4% to 4.8% Mg, and preferably 0.7% to 4.5% Mg.

Claims

1. A rolled composite aerospace product comprising a 2XXX-series core layer and an Al—Mg alloy clad layer coupled to at least one surface of the 2XXX-series core layer, wherein the Al—Mg alloy is a 5XXX-series aluminium alloy comprising 0.4% to 4.8% Mg, and preferably 0.7% to 4.5% Mg.

2. The rolled composite aerospace product according to claim 1, wherein the Al—Mg alloy is a 5XXX-series aluminium alloy having a composition of, in wt. %: Mg 0.4% to 4.8%, preferably 0.7% to 4.5%, Si up to 0.3%, Fe up to 0.5%, Sc up to 0.5%, Mn up to 1.5%, Cu up to 0.2%, Cr up to 0.25%, Zr up to 0.25%, Zn up to 0.5%, Ti up to 0.2%, impurities each <0.05%, total <0.15%, and balance aluminium.

3. The rolled composite aerospace product according to claim 1, wherein the Al—Mg alloy is a 5XXX-series aluminium alloy comprising, in wt. %: Mg 0.4% to 3.0%, preferably 0.4% to 2.5%, Si up to 0.3%, preferably up to 0.25%, Fe up to 0.5%, preferably up to 0.40%, Sc up to 0.04%, preferably up to 0.02%, Mn up to 1.5%, preferably up to 1%, Cu up to 0.2%, preferably up to 0.10%, Cr up to 0.25%, preferably up to 0.15%, Zr up to 0.25%, preferably up to 0.15%, Zn up to 0.5%, preferably up to 0.35%, Ti up to 0.2%, preferably up to 0.10%, impurities each <0.05%, total <0.15%, and balance aluminium.

4. The rolled composite aerospace product according to claim 1, wherein the Al—Mg alloy is a 5XXX-series aluminium alloy comprising, in wt. %: Mg 3.0% to 4.8%, preferably 3.5% to 4.5%, Sc 0.02% to 0.5%, preferably 0.02% to 0.40%, Mn up to 1%, preferably 0.3% to 1.0%, Zr up to 0.25%, preferably 0.05% to 0.2%, Cr up to 0.3%, Ti up to 0.2%, Cu up to 0.25%, Zn up to 0.5%, Fe up to 0.5%, Si up to 0.3%, impurities each <0.05%, total <0.15%, and balance aluminium.

5. The rolled composite aerospace product according to claim 1, wherein the Al—Mg alloy clad layer is coupled by means of roll bonding to the at least one surface of the 2XXX-series core layer.

6. The rolled composite aerospace product according to claim 1, wherein the Al—Mg alloy clad layer has a thickness in the range of 1% to 20%, and preferably 1% to 10%, of the total thickness of the rolled composite aerospace product.

7. The rolled composite aerospace product according to claim 1, consisting of a 2XXX-series core layer and an Al—Mg alloy clad layer coupled to one surface of the 2XXX-series core layer.

8. The rolled composite aerospace product according to claim 1, consisting of a 2XXX-series core layer and an Al—Mg alloy clad layer coupled to both surfaces of the 2XXX-series core layer.

9. The rolled composite aerospace product according to claim 1, wherein an interliner is positioned between the 2XXX-series core layer and the Al—Mg alloy layer, and wherein the interliner is made from a different aluminium alloy than the Al—Mg alloy layer and has a Mg-content lower than the Al—Mg alloy.

10. The rolled composite aerospace product according to claim 1, wherein the 2XXX-series alloy of the core layer (20) has a composition of, in wt. %, Cu 1.9% to 7.0%, preferably 3.0% to 6.8%, more preferably 3.2% to 4.95%, Mg 0.30% to 1.8%, preferably 0.35% to 1.8%, Mn up to 1.2%, preferably 0.2% to 1.2%, Si up to 0.40%, Fe up to 0.40%, Cr up to 0.35%, Zn up to 1.0%, Ti up to 0.15%, Zr up to 0.25, V up to 0.25%, Li up to 2.0% Ag up to 0.80%, Ni up to 2.5%, balance being aluminium and impurities.

11. The rolled composite aerospace product according to claim 1, wherein the 2XXX-series core layer (20) is from the 2×24-series alloy.

12. The rolled composite aerospace product according to claim 1, wherein the 2XXX-series core layer (20) is in a T3, T351, T39, T42, T8 or T851 temper.

13. The rolled composite aerospace product according to claim 1, wherein the rolled composite aerospace product (10) has a total thickness of 0.8 mm to 50.8 mm, and preferably of 0.8 mm to 25.4 mm.

14. The rolled composite aerospace product according to claim 1, wherein the rolled composite aerospace product is an aerospace structural part, and preferably aircraft fuselage.

15. A method of manufacturing a rolled composite aerospace product according to claim 1, comprising the steps of: providing an ingot of a 2XXX-series aluminium alloy for forming the core layer of the composite aerospace product; homogenizing the ingot of the 2XXX-series aluminium alloy at a temperature in the range of 400° C. to 505° C. for at least 2 hours; providing an ingot or rolled clad liner of a 5XXX-series aluminium alloy for forming an outer clad layer on the 2XXX-series core aluminium alloy; optionally homogenizing or preheating the ingot of the 5XXX-series aluminium alloy, preferably at a temperature in the range of at least 470° C., preferably in a range of 480° C. to 570° C., for at least 0.5 hour; roll bonding the 5XXX-series aluminium alloy to the 2XXX-series core alloy to form a roll bonded product, preferably by means of hot rolling, and optionally followed by cold rolling; solution heat-treating the roll bonded product at a temperature in the range of 450° C. to 505° C.; cooling of the solution heat-treated roll bonded product to below 100° C., and preferably to ambient temperature; optionally stretching of the solution heat-treated and cooled roll bonded product; and ageing of the cooled roll bonded product.

16. The method according to claim 15, wherein the method further comprises forming of the solution heat-treated and cooled roll bonded product, and optionally also being stretched, in a forming process into a predetermined shape product.

17. The method according to claim 15, wherein a forming step (j) is performed after the ageing step (i).

18. The method according to claim 17, wherein the forming step (j) and the ageing step (i) are combined in a forming step at elevated temperature, preferably at a temperature in a range of 140° C. to 200° C., and preferably for a time in a range of 1 to 50 hours.

Description

DESCRIPTION OF THE DRAWINGS

[0130] The invention shall also be described with reference to the appended drawings, in which:

[0131] FIG. 1 is a schematic diagram of a rolled composite aerospace product according to an embodiment of the invention;

[0132] FIG. 2 is a schematic diagram of a rolled composite aerospace product having five distinct layers in accordance with certain illustrative embodiments of the invention.

[0133] FIG. 3 is a schematic flow schedule of several embodiments of the process to manufacture a rolled composite aerospace product according to this invention.

[0134] FIG. 1 illustrates the embodiment of a rolled composite aerospace product 10 consisting of a three-layered structure of a 2XXX-series core alloy layer 20 having on each side an Al—Mg alloy clad layer 30 of a 5XXX-series aluminium alloy as herein set forth and claimed. Not shown here, but in another embodiment the 2XXX-series core alloy is clad only on one side or face with a 5XXX-series alloy clad liner.

[0135] FIG. 2 illustrates the embodiment of a rolled composite aerospace product 10 having a five-layered structure consisting of a 2XXX-series core alloy layer 20 having on each side a 5XXX-series aluminium alloy clad layer 30 as herein set forth and claimed, and wherein another and different aluminium alloy interliner or clad layer 40 is interposed between the core alloy layer 20 and the 5XXX-series alloy clad layer 30 such that the 5XXX-series alloy clad layer 30 forms the outer layer of the rolled composite aerospace product 10. The interliner or clad layer 40 is also made of an aluminium alloy having a lower Mg-content than the 5XXX-series alloy clad layer 30.

[0136] FIG. 3 is a schematic flow schedule of several embodiments of the process of this invention to manufacture a rolled composite aerospace product. In process step 1 an ingot is cast of a 2XXX-series alloy forming the core alloy of the composite aerospace product, which optionally can be scalped in step 2 to remove segregation zones near the as-cast surface of the rolling ingot and to increase product flatness. In process step 3 the rolling ingot is homogenized. In parallel in process step 4 an ingot is cast of a 5XXX-series alloy for forming at least one clad layer on a surface of the core alloy of the composite aerospace product, and optionally on both faces of the core alloy. Also this ingot optionally can be scalped in step 5. In process step 6 the 5XXX-series alloy is pre-heated to the hot rolling start temperature and subsequently in process step 7 hot rolled to form liner plate(s) as the clad layer is usually much thinner than the core. In process step 8 the 2XXX core alloy and a 5XXX-series alloy liner plate on one or both sides of the core alloy are roll bonded, preferably by means of hot rolling.

[0137] Depending on the desired final gauge, the roll bonded product can be cold rolled in process step 9 to final gauge, for example to a sheet product or a thin gauge plate product. In a process step 10 the rolled aerospace product is solution heat treated, next cooled in process step 11, and preferably stretched in process step 12.

[0138] In an embodiment the cooled product is formed in forming process 13 and ageing, i.e. natural or artificial ageing, in process step 14 to final temper, e.g. a T3 or T8 temper.

[0139] In an embodiment the forming process 13 and the ageing of process step 14 can be combined, for example the forming operation is performed at a temperature in a range of 140° C. to 200° C., and preferably for a time in a range of 1 to 50 hours, such that also artificial ageing of both the 2XXX-series core and the 5XXX-series clad layer(s) occurs.

[0140] In an embodiment the cooled product is aged in process step 14, i.e. natural or artificial ageing, to a desired temper, and subsequently formed in a forming process 13 into a formed product of predetermined shape.

[0141] In an alternative embodiment after rolling bonding of the 2XXX-series core and the 5XXX-series clad layer(s) to final gauge, the rolled product is formed in a forming process 13 into a predetermined shape, solution heat treated of the formed product in process step 15 and cooled in process step 11 and followed by ageing, i.e. natural or artificial ageing, in process step 14 to final temper, e.g. a T3 or T8 temper.

[0142] The invention is not limited to the embodiments described before, and which may be varied widely within the scope of the invention as defined by the appending claims.