METHOD OF MANUFACTURING 2XXX-SERIES ALUMINUM ALLOY PRODUCTS

1 . An aging process of a solution-heat-treated and quenched 2XXX-series aluminum alloy wrought product, comprising the steps of:

(1) aging the product in a first aging step at one or more temperatures within a range of 90° C. to 120° C. for a cumulative period of time of at least 10 hours; and

(2) subsequently aging the product in a second aging step at one or more temperatures within a range of 150° C. to 205° C. for a cumulative period of time of at least 4 hours.

2 . The aging process according to claim 1 , wherein the aging process is of a solution-heat-treated, quenched, and subsequently cold worked or cold formed 2XXX-series aluminum alloy product.

3 . The aging process according to claim 1 , wherein cold working is applied in one or more cold working steps which are applied after solution heat treatment and quenching, optionally after further natural aging, and either before final artificial aging or in between the two artificial aging steps.

4 . The aging process according to claim 3 , wherein the quenching from solution heat treatment for a plate in a thickness range of 1.6 to 12 mm is performed at a rate between 100° C./min and 1000° C./min.

5 . The aging process according to claim 4 , wherein the quenching from solution heat treatment for a plate in a thickness range of 1.6 to 12 mm is performed at a rate between 200° C./min and 600° C./min.

6 . The aging process according to claim 1 , wherein the aging process is of a worked product to provide a wrought product, solution-heat-treated, quenched, and subsequently cold worked or cold formed 2XXX-series aluminum alloy product.

7 . The aging process according to claim 1 , wherein the second aging step is for a cumulative period of time of at least 12 hours.

8 . The aging process according to claim 7 , wherein the second aging step is for a cumulative period of time of 12 hours to 144 hours.

9 . The aging process according to claim 1 , wherein the 2XXX-series aluminum alloy comprises, in wt. %:

Cu

3.0% to 5.5%;

Mn

0.15% to 1.0%; 

Mg

0.2% to 1.8%;

Ag

    up to 0.7%;

Zr

      up to 0.25%;

Zn

      up to 0.25%;

impurities up to 0.15%; and aluminum.

10 . The aging process according to claim 1 , wherein the 2XXX-series aluminum alloy comprises, in wt. %:

Cu

3.0% to 5.5%;   

Mn

0.15% to 1.0%;     

Mg

0.2% to 1.8%;   

Ag

up to 0.7%;

Zn

up to 1.0%;

Fe

up to 0.3%;

Si

up to 0.2%;

Ti

0.01% to 0.2%;     

optionally one or more dispersoid forming elements selected from the group consisting of 0.05% to 0.25% Cr, 0.05% to 0.25% Zr, 0.05% to 0.25% V, 0.05% to 0.4% Hf, 0.05% to 0.4% Sc; impurities up to 0.15%; and aluminum.

11 . The aging process according to claim 1 , wherein the 2XXX-series aluminum alloy comprises Ag in a range of 0.1% to 0.7%.

12 . The aging process according to claim 1 , wherein the 2XXX-series aluminum alloy comprises a Cu content in a range of 3.5% to 4.4%.

13 . The aging process according to claim 1 , wherein the 2XXX-series aluminum alloy comprises a Cu content in a range of 4.4% to 5.5%.

14 . The aging process according to claim 13 , wherein the 2XXX-series aluminum alloy comprises a Cu content in a range of 4.4% to 5.1%.

15 . The aging process according to claim 1 , wherein the 2XXX-series aluminum alloy is provided as a rolled product.

16 . The aging process according to claim 15 , wherein the rolled product is an aircraft structural member.

17 . A method of manufacturing a 2XXX-series aluminum alloy wrought product, the method comprising the following steps:

(i) casting of an ingot of an 2XXX-series aluminum alloy having a composition according to claim 1 ;

(ii) preheating and/or homogenizing the ingot;

(iii) hot working the ingot by one or more methods selected from the group consisting of rolling, extrusion, and forging, into a hot worked wrought product;

(iv) optionally cold working the hot worked wrought product;

(v) solution heat treating (“SHT”) the wrought product;

(vi) rapid cooling or quenching the SHT product;

(vii) optionally cold working or cold forming the SHT and quenched product; and

(viii) artificial aging in accordance with of the SHT, quenched product and optionally cold working or cold forming.

18 . A wrought 2XXX-series aluminum alloy product, optionally having a clad layer on one or two sides, according to claim 1 , wherein said product having a cross-sectional thickness from 1.6 mm to 12 mm is aged to achieve:

(1) a conventional tensile yield strength (in MPa) measured in L-direction of more than 400 MPa; or

(2) an improved IGC resistance measured without cladding showing predominantly pitting attack and negligent IGC.

19 . A wrought 2XXX-series aluminum alloy product according to claim 1 , wherein said product having a cross-sectional thickness from 12 mm to 250 mm is aged to achieve:

(1) a conventional tensile yield strength (in MPa) measured in L-direction at quarter thickness of more than 380 MPa+0.57 (120−t) MPa, wherein t is the thickness of the product in mm; or

(2) a minimum service life without failure due to stress corrosion cracking in accordance with ASTM G47 of at least 20 days, preferably of at least 25 days at a short transverse stress level of 250 MPa.

20 . A wrought 2XXX-series aluminum alloy product according to claim 1 , wherein said product having a cross-sectional thickness from 12 mm to 250 mm is aged to achieve:

(1) a conventional tensile yield strength (in MPa) measured in L-direction at quarter thickness of more than 380 MPa+0.57 (120−t) MPa, wherein t is the thickness of the product in mm; or

(2) an improved IGC resistance measured without cladding showing predominantly pitting attack and negligent IGC.