Influence of heat treatment on mechanical properties and microstructure of EN AW 6082 aluminum alloy

The mechanical properties and microstructure of heat treated 6082 wrought aluminum alloy was studied. The aim of this work was to study the merits and demerits of natural aging and artificial aging on material properties. The precipitation hardening of aluminum alloy usually undergoes a thermal treatment consisting of heat treatment, quenching and aging. Experiments were carried out for different natural aging time (10 min, 30 min, 60 min and 120 min) and at different artificial aging temperatures (150 °C–210 °C at an interval of 10°C). The results were analyzed with optical microscope, scanning electron mic roscope (SEM), XRD and transmission electron microscope (TEM). The results showed that the type and distribution of precipitates significantly affect the mechanical properties. Natural aging affect the formation of metastable (Mg <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf> Si <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</inf> ) precipitates and stable (Mg <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> Si) precipitates, Peak hardness (strength) is achieved by metastable precipitates. As the natural aging time increases sides for the nucleation of precipitated decreases, hence the strength decreases.