Effect of quenching rate on microstructure and mechanical properties of commercial AA7108 aluminium alloy
(1. SINTEF Materials and Chemistry, NO-7465, Trondheim, Norway;
2. Department of Materials Science and Engineering, Norwegian University of Science and Technology,
NO-7491, Trondheim, Norway;
3. Benteler Aluminium Systems Norway AS, NO-2830, Raufoss, Norway)
2. Department of Materials Science and Engineering, Norwegian University of Science and Technology,
NO-7491, Trondheim, Norway;
3. Benteler Aluminium Systems Norway AS, NO-2830, Raufoss, Norway)
Abstract: A commercial AA7108 aluminium alloy subjected to different quenching procedures from the solid solution temperature of 480 °C was considered. Both continuously cooling and quenching to intermediate temperatures (400, 300 and 200 °C) followed by different holding times were applied. All the materials were subsequently subjected to the same industrial two-step artificial ageing procedure to obtain a maximum strength (T6). Tensile testing of the different quenched materials in the T6 temper reveals a large deviation in strength dependent on the cooling/holding time, compared with the reference sample. A collection of the different quenched materials was chosen for further investigation of the precipitate structure by transmission electron microscopy (TEM) to explain the differences in mechanical properties.
Key words: aluminium; microstructure; precipitate free zone; mechanical properties