Study on quench sensitivity of A357 alloy

The precipitation phases and mechanical properties of A357-T6 alloy in different quenching conditions were investigated in order to study the sensitivity of casting mechanical properties to quenching conditions. The results show that the strength and macrohardness of the T6 heat treated alloy increase and the relative elongation decrease slightly with increasing quenching cooling rate. The strength and macrohardness of the alloy transfer decrease and the relative elongation increases firstly and then decreases with increasing the quenching time. Differential Scanning Calorimetry (DSC) test results show that the different mechanical properties of the A357-T6 alloy results from the different amount of β′-Mg₂Si precipitation phase and the change of morphology of Si phase in different quenching conditions.