CLAD 2XXX-SERIES AEROSPACE PRODUCT

Abstract

The invention relates to a rolled composite aerospace product (10) comprising a 2XXX-series core layer (20), preferably an AA2024-series aluminium alloy, and an Al—Mn alloy layer (30) coupled to at least one surface of the 2XXX-series core layer, and wherein the Al—Mn alloy layer (30) is of a 3XXX-series aluminium alloy comprising 0.3% to 2.0% Mn.

Claims

1. A rolled composite aerospace product (10) comprising a 2XXX-series core layer (20) and an Al—Mn alloy layer (30) coupled to at least one surface of the 2XXX-series core layer and wherein the Al—Mn alloy layer (30) is of a 3XXX-series aluminium alloy comprising 0.3% to 2.0% Mn.

2. The rolled composite aerospace product according to claim 1, wherein the Al—Mn alloy layer (30) is of a 3XXX-series aluminium alloy having a composition of, in wt. %: TABLE-US-00005 Mn 0.5 to 2.0, Si up to 1.2, Fe up to 0.7, Cu up to 1.5, Mg up to 1.0, Cr up to 0.25, Zr up to 0.25, Ti up to 0.25, Zn up to 1.5, other elements and impurities each <0.05, total <0.15; balance aluminium.

3. The rolled composite aerospace product according to claim 2, wherein the Mg-content is in a range of 0.1% to 0.7% and the Cu-content is in a range of 0.20% to 1.2%.

4. The rolled composite aerospace product according to claim 2, wherein the Mg-content is in a range of 0.1% to 0.7% and the Cu-content is up to 0.25%.

5. The rolled composite aerospace product according to claim 2, wherein the Mg-content is up to 0.25% and Cu-content is in a range of 0.20% to 1.2%.

6. The rolled composite aerospace product according to claim 2, wherein the Mg-content is up to 0.20% and the Cu-content is up to 0.25%.

7. The rolled composite aerospace product according to claim 1, wherein the Al—Mn alloy layer (30) is non-homogenized.

8. The rolled composite aerospace product according to claim 1, wherein the Al—Mn alloy layer (30) is homogenized.

9. The rolled composite aerospace product according to claim 1, wherein the Al—Mn alloy layer (30) is coupled by means of roll bonding to the at least one surface of the 2XXX-series core layer (20).

10. The rolled composite aerospace product according to claim 1, wherein each Al—Mn alloy layer (30) has a thickness in the range of 1% to 20% of the total thickness of the rolled composite aerospace product (10).

11. The rolled composite aerospace product according to claim 1, consisting of a 2XXX-series core layer (20) and an Al—Mn alloy layer (30) coupled to one surface of the 2XXX-series core layer (20).

12. The rolled composite aerospace product according to claim 1, consisting of a 2XXX-series core layer (20) and an Al—Mn alloy layer (30) coupled to both surfaces of the 2XXX-series core layer (20).

13. 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. %, TABLE-US-00006 Cu 1.9% to 7.0%; Mg 0.30 % to 1.8%, Mn up 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%; and balance being aluminium and impurities.

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

15. 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.

16. The rolled composite aerospace product according to claim 1, wherein an interliner (40) is positioned between the 2XXX-series core layer (20) and the Al—Mn alloy layer (30), and wherein the interliner (40) is made from a different 3XXX-series aluminium alloy than the Al—Mn alloy layer (30), the interliner (40) being made from a 3XXX-series aluminium alloy comprising 0.3% to 2.0% Mn and 0.25% to 4% Zn.

17. The rolled composite aerospace product according to claim 1, wherein an interliner (40) is positioned between the 2XXX-series core layer (20) and the Al—Mn alloy layer (30), and wherein the interliner (40) is made from a different 3XXX-series aluminium alloy than the Al—Mn alloy layer (30), the interliner (40) being made from a 3XXX-series aluminium alloy comprising, in wt. %, TABLE-US-00007 Mn 0.3% to 2.0%; Zn 0.25% to 4%; Si to 1.2%; Fe to 0.7%; Cu to 1.5%; Mg to 1.0%; Cr up to 0.25%; Zr up to 0.25%; Ti up to 0.25%; and other elements and impurities each <0.05%, total <0.15%, and balance aluminium.

18. 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.

19. The rolled composite aerospace product according to claim 1, wherein the rolled composite aerospace product is an aerospace structural part.

20. 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 3xxx-series aluminium alloy for forming an outer clad layer on the 2xxx-series core aluminium alloy; optionally homogenizing the ingot of the 3xxx-series aluminium alloy at a temperature in the range of at least 450° C. for at least 1 hour; roll bonding the 3xxx-series aluminium alloy to the 2xxx-series core alloy to form a roll bonded product, 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.; optionally stretching of the solution heat-treated and cooled roll bonded product; and ageing of the cooled roll bonded product.

21. The method according to claim 20, 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 with a uniaxial or a biaxial curvature.

22. The method according to claim 20, wherein a forming step is performed after the ageing step.

23. The method according to claim 21, wherein the forming step and the ageing step are combined in a forming step at elevated temperature.

Description

DESCRIPTION OF THE DRAWINGS

[0079] The invention shall also be described with reference to the appended drawings, in which FIGS. 1 and 2 are each a schematic diagram showing embodiments of the invention.

[0080] FIG. 1 is a schematic diagram of a rolled composite aerospace product having three distinct layers in accordance with certain illustrative embodiments.

[0081] FIG. 2 is a schematic diagram of a rolled composite aerospace product having five distinct layers in accordance with certain illustrative embodiments.

[0082] FIG. 3 is a schematic flow schedule of several embodiments of the process to manufacture a rolled composite aerospace product according to this invention.

[0083] FIG. 1 illustrates the embodiment of a rolled composite aerospace product 10 having a three-layered structure of a 2XXX-series core alloy layer 20 having on each side an Al—Mn alloy clad layer 30 of a 3XXX-series aluminium alloy as herein set forth and claimed.

[0084] 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 an Al—Mn alloy clad layer 30 of a 3XXX-series aluminium alloy as herein set forth and claimed, and wherein another Al—Mn alloy clad layer 40 is interposed between the core alloy layer 20 and the Al—Mn alloy clad layer 30 such that the Al—Mn alloy clad layer 30 forms the outer layer of the rolled composite aerospace product 10. The Al—Mn alloy clad layer 40 is also made of a 3XXX-series having a higher Zn-content than the 3XXX-series alloy of the Al—Mn alloy clad layer 30, and the Al—Mn alloy clad layer 40 has a composition as herein described and claimed.

[0085] 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 an Al—Mn alloy or 3XXX-series aluminium 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 Al—Mn alloy or 3XXX-series aluminium alloy is either homogenized and pre-heated to the hot rolling start temperature or non-homogenized and only 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 an 3XXX-series aluminium alloy liner plate on one or both sides of the core alloy are roll bonded, preferably by means of hot rolling. 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.

[0086] In an embodiment the cooled product is formed in forming process 13 and aged, i.e. natural or artificial ageing, in process step 14 to final temper, e.g. a T3 or T8 temper.

[0087] 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 about 140° C. to 200° C., and preferably for a time in a range of about 1 to 50 hours, such that also artificial ageing of both the 2XXX-series core and the 3XXX-series alloy clad layer(s) occurs.

[0088] 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.

[0089] In an alternative embodiment after rolling bonding of the 2XXX-series core and the 3XXX-series aluminium alloy 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.

[0090] 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.