Al-Cu-Li-Mg-Mn-Zn ALLOY WROUGHT PRODUCT
An aluminium alloy wrought product for structural members having a chemical composition of, in wt. %: Cu 3.2% to 4.4%, Li 0.8% to 1.4%, Mg 0.20% to 0.90%, Mn 0.10% to 0.8%, Zn 0.20% to 0.80%, one or more elements selected from the group of: (Zr 0.05% to 0.25%, Cr 0.05% to 0.30%, Ti 0.01% to 0.25%, Sc 0.05% to 0.4%, Hf 0.05% to 0.4%), Ag<0.08%, Fe<0.15%, Si<0.15%, unavoidable impurities and balance aluminium.
1 . An aluminium alloy wrought product for structural members having a chemical composition consisting of, in wt. %:
Cu
3.2 to 4.4
Li
0.8 to 1.4
Mg
0.20 to 0.90
Mn
0.10 to 0.8
Zn
0.20 to 0.80,
one or more elements selected from the group consisting of:
Zr
0.05 to 0.25,
Cr
0.05 to 0.30,
Ti
0.01 to 0.25,
Sc
0.05 to 0.4,
Hf
0.05 to 0.4,
Ag
<0.08
Fe
<0.15
Si
<0.15,
unavoidable impurities and balance aluminium.
2 . An aluminium alloy wrought product according to claim 1 , wherein the Cu content is in a range of 3.6% to 4.4%.
3 . An aluminium alloy wrought product according to claim 1 , wherein the Li content is in a range of 0.90% to 1.4%.
4 . An aluminium alloy wrought product according to claim 1 , wherein the product contains Zr in a range of 0.05% to 0.15%.
5 . An aluminium alloy wrought product according to claim 1 , wherein the Zn-content is maximum 0.70%.
6 . An aluminium alloy wrought product according to claim 1 , wherein the Ag content is less than 0.05%.
7 . An aluminium alloy wrought product according to claim 1 , wherein the product contains Mn in a range of 0.20% to 0.6%.
8 . An aluminium alloy wrought product according to claim 1 , wherein the product contains Mg in a range of 0.20% to 0.8%.
9 . An aluminium alloy wrought product according to claim 1 , wherein the product is in the form of a rolled, extruded or forged product.
10 . An aluminium alloy wrought product according to claim 9 , wherein the wrought product is in the form of an extruded product.
11 . An aluminium alloy wrought product according to claim 1 , wherein the wrought product is in the form of a plate product having a thickness of 12.0 mm to 175 mm.
12 . An aluminium alloy wrought product according to claim 9 , wherein said wrought product has been treated with a hot deformation operation, a solution heat-treatment followed by quenching, and artificial ageing.
13 . An aluminium alloy wrought product according to claim 9 , wherein said wrought product has been treated with a solution heat-treatment followed by quenching, cold strain-hardening, and possesses a permanent deformation between 0.5% and 15%.
14 . An aluminium alloy wrought product according to claim 1 , wherein the product is in an under-aged T8 condition.
15 . The method of manufacturing an aluminium alloy wrought product according to claim 1 , comprising the steps of:
a. casting stock of an ingot of an AlCuLi-alloy according to claim 1 ,
b. preheating and/or homogenizing the cast stock;
c. hot working the stock by one or more methods selected from the group consisting of rolling, extrusion, and forging;
d. optionally cold working the hot worked stock;
e. solution heat treating (SHT) of the hot worked and/or optionally cold worked stock, the SHT is carried out at a temperature and time sufficient to place into solid solution the soluble constituents in the aluminium alloy;
f. cooling the SHT stock;
g. optionally stretching or compressing the cooled SHT stock or otherwise cold working the cooled SHT stock to relieve stresses; and
h. ageing, preferably artificial ageing, of the cooled and optionally stretched or compressed or otherwise cold worked SHT stock to achieve a desired temper.
16 . The method according to claim 15 , wherein homogenisation is performed at a temperature in a range of 475° C. to 535° C.
17 . The method according to claim 15 , wherein the hot-working is by rolling and the hot-working entry temperature is at a temperature in the range of 440° C. to 490° C.
18 . The method according to claim 15 , wherein the solution heat treatment is performed at a temperature in a range of 480° C. to 525° C.
19 . The method according to claim 15 , wherein the stretching is per-formed in a range of 0.5% to 6%.
20 . The method according to claim 15 , wherein the product has been aged to an under-aged T8 condition.
21 . The method according to claim 15 , wherein the wrought product is rolled to a plate product having a thickness of at least 12.0 mm.
22 . An aluminium alloy wrought product according to claim 1 , wherein the Cu content is in a range of 3.75% to 4.20%.
23 . An aluminium alloy wrought product according to claim 1 , wherein the Li content is in a range of 1.0% to 1.30%.
24 . An aluminium alloy wrought product according to claim 1 , wherein the alloy product is substantially Ag-free.
25 . An aluminium alloy wrought product according to claim 1 , wherein the product contains Mn in a range of 0.20% to 0.55%.
26 . An aluminium alloy wrought product according to claim 1 , wherein the product contains Mg in a range of 0.20% to 0.65%.
27 . An aluminium alloy wrought product according to claim 1 , wherein the product contains Mg in a range of 0.35% to 0.65%.
28 . An aluminium alloy wrought product according to claim 9 , wherein said wrought product has been treated with a solution heat-treatment followed by quenching, cold strain-hardening, and possesses a permanent deformation between 0.5% and 6%.
29 . The method according to claim 15 , wherein otherwise cold working the cooled SHT stock to relieve stresses one or more of levelling or drawing or cold rolling of the cooled SHT stock