IN SITU STUDY ON THE EVOLUTION OF DENDRITE MORPHOLOGY AFFECTED BY ELECTRIC FIELD IN Sn-Bi ALLOY

摘要

With high energy, high brilliance and eminent collimation, synchrotron X-ray imaging enables in situ observation of dendrite growth during the solidification of Sn-Bi alloy under an applied electric field such as direct current (DC) and electric current pulse (ECP). In present study, the application of DC leads to the suppression of dendrite growth and the degeneration of the secondary and higher order dendrites. Due to the induced Joule heat, the sharp dendrite tips are modified to be round or flat. By applying ECP to the sample during the whole solidification process, a significant grain refinement is observed.