US Patent 7604704 Balanced Al-Cu-Mg-Si alloy product

The present invention concerns a balanced Al—Cu—Mg—Si alloy having a high toughness, good strength levels and an improved fatigue crack growth resistance, comprising essentially the following composition (in weight percent): Cu: 3.6-4.9, Mg: 1.0-1.8, Mn:≦0.50, preferably <0.30, Si: 0.10-0.40, Zr:≦0.15, Cr:≦0.15, Fe:≦0.10, the balance essentially aluminum and incidental elements and impurities. There is also disclosed a method for producing the balanced Al—Cu—Mg—Si alloy product having a high toughness and an improved fatigue crack growth resistance, and applications of that product as a structural member of an aircraft.