Recently, pure aluminum metal or aluminum alloys have been widely used as conductors. With the consideration that this
metal is much lighter than copper, unfortunately its strength is relatively lower. The purpose of this study was to determine
the effect of heat treatment on the hardness and electrical conductivity of Al-Si-Mg (A383) alloys. Heat treatment was carried out in 2 stages, namely heat treatment of specimens subjected to solution heat treatment of 550oC with a holding time of 2 hours and then quenched in water media. Furthermore, in the second stage, the specimens were aged with artificial aging at temperatures of 100, 150 and 200oC with holding times of 30, 60 and 90 minutes. The tests carried out are the composition test, the Brinnel hardness test and the electrical conductivity test. The results showed that increasing the aging temperature and the amount of silicon elements increased the hardness of aluminum. The maximum electrical conductivity condition of 0.325 mS/cm is obtained at a holding time of 150 minutes and an aging temperature of 200C. The optimal condition for the best hardness and electrical conductivity is an aging temperature of 200oC and holding time 88o minutes or an aging temperature of 100oC with a holding time of 30 minutes.