Abstract
The influence of solid solution temperature, water quenching temperature, transfer time before quenching and delay time after quenching on the mechanical properties and conductivity of 7A09 aluminum alloy were investigated. The mechanical properties and conductivity keep relatively stable at the range of 460–490 °C. When the transfer time before quenching is more than 20 s or the water quenching temperature is higher than 40 °C, the strength and conductivity drop remarkably while the elongation keeps rising all the time. Before the delay time is 8 h, the strength drops quickly while the elongation and conductivity rise continuously. In the range of 8–24 h there is an opposite change compared to the previous 8 h. Once the delay time exceeds 24 h, all the properties become stable. The optimal quenching parameters are as follows: the solid solution temperature is 460–490 °C, and the water quenching temperature and the transfer time before quenching are below 40 °C and 20 s, and the delay time after quenching is below 2 h or above 24 h.

Key words
quenching parameters, 7A09 aluminum alloy, mechanical properties, conductivity

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