Patent ID: 7815758

Claim:
A method for producing a rolled high damage tolerant AA2xxx-series alloy product and having a high toughness and an improved fatigue crack growth resistance, comprising the steps of: a) casting an ingot comprising the following composition (in weight percent): Cu: 3.8-4.7 Mg: 1.0-1.6 Zr: 0.06-0.18 Mn: >0-0.50 Fe: ≦0.15 Si: ≦0.15, the balance essentially aluminum and incidental elements and impurities, b) homogenizing and/or pre-heating the ingot after casting, c) hot rolling the ingot and optionally cold rolling into a rolled product, d) solution heat treating, e) quenching the heat treated product, f) stretching in the quenched product, and g) naturally ageing the rolled and heat-treated product to provide a T3 condition; and wherein the alloy product comprises Mn-containing dispersoids and Zr-containing dispersoids, wherein the alloy product has a microstructure wherein the grains have an average length to width aspect ratio of smaller than about 3 to 1.