Application of 7xxx series aluminum alloy in automobile
7××× series aluminum alloys are mainly composed of Zn, Mg, and Cu as the main alloying elements, and the main strengthening phase is the η (MgZn2) phase, which is also an alloy that can be strengthened by heat treatment. The η phase has the characteristics of fine and dispersed distribution, and the alloy contains a high fraction of precipitated phases, which makes the strength of the 7××× series alloys significantly higher than that of other series.
The development of 7××× series aluminum alloys has gone through 4 stages: the first stage is to develop alloys with high strength and low toughness; Corrosion alloys; in the third stage, through the adjustment of alloy composition, the toughness of the alloy is improved, forming a high-strength, high-toughness and corrosion-resistant alloy; Corroded alloy. Heat treatment process and alloying exploration play an important role in the development of alloys. Different composition ratios and different heat treatment processes will bring different properties to the alloy.
The strength of 7××× series aluminum alloy can meet the bearing requirements of automobile structural parts, but in the peak aging state, the elongation of the alloy is low, indicating that the formability of the alloy is poor. When it is used as an automobile sheet, it is necessary to improve the heat treatment. process, to find a suitable forming method.