PROCESS FOR THE PREPARATION OF A HIGH RESISTANCE AI-Zn-Mg-Cu ALLOY

摘要

The present invention relates to a process for the preparation of a high strength Al-Zn-Mg-Cu alloy, which has improved tensile strength and high damage tolerance, including the molding steps of an ingot having the following composition (in weight percent): Zn 5.5-9.5, Cu 1.5-3.5, Mg 1.5-3.5, Mn 0.25 Zr 0.25 , Cr 0, 10, Fe 0, 25, Si 0, 25, Ti 0, 10, Hf and / or V 0, 25, other elements each present in a proportion of less than 0.05 % and in total in a proportion of minus 0, 15%, the balance being aluminum, homogenization and / or preheating the ingot after molding, hot working and possibly cold working to obtain a more worked product 50 mm thick, solution heat treatment, quenching of the solution heat treatment product, and artificial aging of the worked and heat-treated product, the artificial aging step comprising a first heat treatment at a temperature of 105 to 135 ° C for more than two hours to less than 8 hours and a second heat treatment at a temperature of more than 135 ° C but less than 170 ° C for more than 5 hours to less than 15 hours. The present invention relates to a plate weldable product prepared from such Al-ZnMg-Cu alloy having a thickness of more than 50 mm and a prepared aircraft structural part of such alloy. / P