Clad 2XXX-series aerospace product

1. A rolled composite aerospace product comprising a 2XXX-series core layer and an Al—Cu alloy clad layer coupled to at least one surface of the 2XXX-series core layer, wherein the Al—Cu alloy clad layer is of an aluminium alloy comprising, in wt. %, 0.2% to 2.8% Cu and 0.2% to 1.5% Mg.

2. The rolled composite aerospace product according to claim 1 , wherein the Al—Cu alloy clad layer is of an aluminium alloy comprising, in wt. %, 0.2% to 1.8% Cu.

3. The rolled composite aerospace product according to claim 1 , wherein the Al—Cu alloy clad layer comprises an aluminium alloy having a composition of, in wt. %:

Cu

0.02% to 2.8%;

Mg

0.02% to 1.5%;

Mn

up to 0.5%;

Si

up to 0.5%;

Fe

up to 0.4%;

Cr

up to 0.25%;

V

up to 0.25%;

Zr

up to 0.2%;

Ag

up to 0.80%;

Zn

up to 0.3%;

Ti

up to 0.2%;

and

balance unavoidable impurities and aluminium.

4. The rolled composite aerospace product according to claim 3 , wherein the Cu-content is in a range of 0.2% to 1.5%.

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

6. The rolled composite aerospace product according to claim 1 , wherein the Al—Cu alloy clad layer has a corrosion potential of −710 mV or less.

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

8. The rolled composite aerospace product according to claim 1 , wherein the Al—Cu alloy clad layer has a thickness in the range of 1% to 20% of the total thickness of the rolled composite aerospace product.

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

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

11. The rolled composite aerospace product according to claim 10 , wherein the interliner is made of a 1 XXX-series aluminium alloy.

12. The rolled composite aerospace product according to claim 1 , wherein the 2XXX-series core layer has a composition of, in wt. %,

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.

13. The rolled composite aerospace product according to claim 1 , wherein the 2XXX-series core layer is from a 2X24-series alloy.

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

15. The rolled composite aerospace product according to claim 1 , wherein the rolled composite aerospace product has a total thickness of 0.8 mm to 50.8 mm.

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

17. 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 510° C. for at least 2 hours;

providing an ingot or rolled clad liner of an Al—Cu aluminium alloy for forming an outer clad layer on the 2XXX-series core aluminium alloy;

optionally homogenizing or preheating the ingot of the Al—Cu aluminium clad alloy forming an outer clad layer at a temperature in the range of at least 400° C. for at least 0.5 hour;

roll bonding the Al—Cu alloy clad layer to the 2XXX-series core alloy to form a roll bonded product, and optionally followed by cold rolling;

solution heat-treating the roll bonded product at a temperature in the range of 450° C. to 510° 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.

18. The method according to claim 17 , 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.

19. The method according to claim 17 , wherein a forming step is performed after the ageing step.

20. The method according to claim 19 , wherein the forming step and the ageing step are combined in a forming step at elevated temperature for a time in a range of 1 to 50 hours.