US 11,970,756 B2
Aluminum alloy and overaged aluminum alloy product of such alloy
Joachim Becker, Meinerzhagen (DE); Matthias Hilpert, Marienheide (DE); Thomas Witulski, Meinerzhagen (DE); and Michael Besel, Meinerzhagen (DE)
Assigned to OTTO FUCHS KOMMANDITGESELLSCHAFT, Meinzerhagen (DE)
Appl. No. 17/052,385
Filed by OTTO FUCHS—KOMMANDITGESELLSCHAFT, Meinerzhagen (DE)
PCT Filed Jul. 2, 2018, PCT No. PCT/EP2018/067740
§ 371(c)(1), (2) Date Nov. 2, 2020,
PCT Pub. No. WO2020/007437, PCT Pub. Date Jan. 9, 2020.
Prior Publication US 2021/0164076 A1, Jun. 3, 2021
Int. Cl. C22C 21/10 (2006.01); C22F 1/053 (2006.01)
CPC C22C 21/10 (2013.01) [C22F 1/053 (2013.01)] 13 Claims
 
1. An aluminum alloy product having a composition consisting of:
0.04-0.1 wt % Si,
0.8-1.8 wt % Cu,
1.5-2.3 wt % Mg,
0.15 to less than 0.35 wt % Ag,
7.05-9.2 wt % Zn,
0.08-0.14 wt % Zr,
0.02-0.08 wt % Ti,
max. 0.35 wt % Mn,
max. 0.1 wt % Fe,
max. 0.06 wt % Cr,
optionally 0.0015-0.0035 wt % Be,
remainder Al in addition to unavoidable impurities, with a Zn/Mg ratio of 3.6-4.4, wherein the Zn and Mg in the Zn/Mg ratio are in weight percent;
wherein the aluminum alloy product has been overaged in accordance with T7451 or T7452 or T7454, the aluminum alloy product having a yield point (Rp0.2) of at least 440 MPa, a fracture toughness (KIc) of at least 20 MPa√m, and no crack propagation after performing an EAC test according to ASTM E1681 using DCB samples according to ASTM G168 under the following conditions:
in air at 50° C.,
at a humidity of 85%,
with a stress of up to 20 MPa√m, and
with a test duration of 30 days.