The relationship between the thermoelectric power and resultant solidification microstructures of Al-Si melt under electromagnetic field

Abstract

In this paper, the thermoelectric power of hypo/hyper-eutectic Al-Si alloys melt induced by electromagnetic fields has been researched, as well as the resultant microstructures evolution corresponding to different stages of thermoelectric power. The results show that the thermoelectric power of Al-Si alloy melt is strongly sensitive to electromagnetic field, showing the sharp increment. Then thermoelectric power gradually gets back to the initial value after turning off the electromagnetic field. As for the resultant microstructures during the recovery stage of the thermoelectric power, TEM are used to capture the results that smaller Si particles grow up from the combination of Si particles after treatment. SEM observation and statistical processing data results about phase size/distribution show the recovery of eutectic Si phases, as well as the α-Al phases, indicating the pseudo growth of Si and Al clusters. Further, a recovery trend of primary Si phases also indicates the pseudo growth of Si clusters. Pseudo growth of clusters is verified by both the thermoelectric power and the resultant solidification microstructures. The recovery solidification microstructures correspond well to the thermoelectric power decrement after treatment.