Retrogression and Reaging – Aluminum Alloy AA7012

Retrogression and Reaging (RRA) is of interest to the automotive industry for manufacturing components of high-strength aluminum alloys. This study describes obtaining the Retrogression and Reaging curve for the aluminum alloy AA7012-T6 (Al-Zn-Mg-Cu) – UNS A97012. The RRA heat treatment consists of two stages: the first stage is retrogression, which was carried out on the samples in the T6 hardening condition for a time ranging from 5 seconds to 4 hours and at different temperatures: 180°C, 210°C, and 240°C. The second stage, re-aging, was conducted at 120°C for 24 hours (process parameters for obtaining the T6 temper). The RRA curve was obtained by measuring hardness Vickers (HV). The samples were also evaluated for electrical conductivity (%IACS - International Annealed Copper Standard ). The best response for the RRA curve was obtained with retrogression at 180°C/1h and re-aging at 120°C for 24 hours. The increase in hardness (HV) obtained with RRA 180°C/1h and reaged at 120°C/24h was 19%.