Solidification Process Center Field On The Flow Control

The low-melting alloys are applied extensively to electron industry field since whose function advantage, and the eutectic alloys of low-melting such as Pb-Sn alloys are especially important. Recently, the study on lead-free product is intensified along with the more and more strict requirement on environmental protection. It's considered that the Sn-Bi, Bi-In, Sn-Zn alloys are good replacement of Pb. However, this alloys can't meet the industrial requirements in natural solidification condition. On the other hand, The research indicated that liquid flow plays an important role in metal's solidification. But the detailed mechanisms of flow during melt solidification process are still unclear, and many questions remained unresolved.In allusion to this phenomenon, Pb-Sn eutectic alloys and Pb-free alloys such as Sn-Bi, Bi-In, Sn-Zn systems are investigated by using the rotating magnetic experiment instruments with 450mT magnetic intensity, The influence of the rotating magnetic field on the solidification process of alloys is studied by comparing the solidification microstructures under the common condition and rotating magnetic field . Besides , we also try to add a little thulium Ce to the alloy, and study the effect on crystalloid organization and alloy wetting ability by combining the rotating magnetic field and the third component to drive the liquid metal to flow. Important results are drawn as following:1. In this paper, the influences of rotating magnetic field and the rare earths Ce on microstructure of solidified Pb-48%Sn hypoeutectic and Pb-67%Sn, Pb-80%Sn hypereutectic are studied. It is found that the rotating magnetic field can eliminate the gravity-induced macrosegregation, result in dendrite fragmentation and raising on mechanical properties, while adding a little Ce to Pb-Sn eutectic, The analysis shows that both the rotating magnetic field and Ce have more effects on the result2. The influences of rotating magnetic field and the rare earths Ce on microstructure of solidified Sn-Bi eutectic are studied in this article. The results...