Al-Zn-Mg Alloy Product with Reduced Quench Sensitivity

摘要

This relates to an aluminum alloy product, in particular an age-hardenable Al—Zn—Mg type alloy product for structural members, the alloy product combining a high strength with high toughness and reduced quench sensitivity, and having a chemical composition including, in wt. %: Zn about 3 to 11%, Mg about 1 to 3%, Cu about 0.9 to 3%, Ge about 0.03 to 0.4%, Si max. 0.5%, Fe max. 0.5%, balance aluminum and normal and/or inevitable elements and impurities. Furthermore, this relates to a method of producing such aluminum alloy products.

主权项

1. A method of manufacturing a wrought aluminium alloy product of an AA7000-series alloy, the method comprising the steps of:
a. casting stock of an ingot of an AA7000-series aluminium alloy comprising an aluminium alloy having a chemical composition comprising, in wt. %:Zn  3 to 11%Mg  1 to 3%Cu 0.9 to 3%Ge0.03 to 0.4%Simaximum 0.5%Femaximum 0.5%Timaximum 0.5%, optionally one or more elements selected from the group consisting of:Mnat most 0.4%,Tiat most 0.3%,Crat most 0.4%,Zrat most 0.5%,Scat most 0.5%,Hfat most 0.3%,Vat most 0.4%,Agat most 0.5%,Liat most 2.5%, and optionally at most:
about 0.05% Ca,about 0.05% Sr,about 0.004% Bebalance aluminium and normal and/or inevitable elements and impurities, said normal and/or inevitable elements and impurities being present each <0.05%, total <0.15%;
b. homogenising the cast stock by heating the stock to a temperature in a range of 430 to 490° C., followed by heating to a temperature in a range of >500 to 550° C., 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 stock and optionally cold worked stock; 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, h. ageing of the cooled and optionally stretched or compressed or otherwise cold worked SHT stock to achieve a desired temper.