Effect of Zr addition on properties of Al–Mg–Si aluminum alloy used for all aluminum alloy conductor

The effects of Zr addition on mechanical property in the aged Al–Mg–Si alloy exposed to thermal-resistant treatment (180–250 °C) have been studied by using both Brinell Hardness tests and tensile tests. The softening process at 180 °C and 230 °C has been investigated by transmission electron microscope (TEM). The Arrhenius Model is introduced to simulate the strength evolution in the thermal-resistant treatment. The results show that tensile strength and thermal-resistant property are improved by addition of Zr, and both the Brinell Hardness and Tensile Strength could maintain no less than 90% of their initial values when the alloy is exposed to heat treatment at 180 °C for 400 h and 230 °C for 2 h. The presence of rod-shaped phases and coarsening particles results in decreasing the hardness of the sample. The relationship between thermal-resistant life and temperature is derived by the Arrhenius Model. When the Al–Mg–Si–Zr alloy is heated at 130 °C, the duration described in the Arrhenius plot could reach to 40 years.