Effect of quenching parameters on the mechanical properties of the 7A04 aluminium alloy

The effects of quenching parameters, including the solid-solution temperature, water temperature of quenching, transfer time before quenching and delay time after quenching on the mechanical properties of the 7A04 aluminium alloy were studied. The experimental results showed that the mechanical properties are relatively stable when the solid-solution temperature is at 460-490 degrees C, but the over-burn will appears once the temperature exceeds 500 degrees C. When the water temperature of quenching and the transfer time before quenching are above 40 degrees C and 20 s, the strengths of the 7A04 alloy will drop remarkably. Before the delay time after quenching is 8 h, the strengths will drop gradually while the elongation will rise continuously. In the range of 8-24 h there is an opposite change of mechanical properties compared to the previous 8 h. Once it exceeds 24 h, the mechanical properties will become stable.