Effects of Different Mold Temperature on Dendrite Morphology of Sn-Bi Alloy in Directional Solidification

The directional solidification process of Sn–10 wt% Bi alloy with low melting point was observed by synchrotron X-ray imaging technology. The mold temperature was controlled, and the dynamic images of a series of alloy solidification behavior were obtained. The results show that columnar crystal grows in dendrite morphology. It is also found that dendrite morphology changes at different mold temperature. With the decrease of the mold temperature, the dendrite morphology begins to change from irregular to regular, and finally, the primary dendrites and the secondary dendrites are perpendicular to each other.