论文名称：In situ synchrotron X-ray imaging on morphological evolution of dendrites in Sn-Bi hypoeutectic alloy under electric currents
论文类型：期刊论文
发表刊物：APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
收录刊物：SCIE、EI、Scopus
卷号：117
期号：3
页面范围：1059-1066
ISSN号：0947-8396
摘要：The growth behavior and morphological evolution of dendrites in solidifying Sn-Bi alloy under electric currents [e.g., direct current (DC) and electric current pulse (ECP)] are in situ studied using synchrotron radiation X-ray imaging technique. The suppression of dendrite growth, floating and rotation of dendrites, refinement and remelting of dendrites are investigated by analyzing a series of animated images captured during the experiments. The modification mechanisms of dendrite morphology by electric fields are discussed based on the in situ and real-time observations. When DC is imposed on the samples, the growth of dendrites is significantly suppressed due to the effect of Joule heat, and a small dendrite freely flows up and rotates due to the common effect of natural convection. When ECP is imposed in the whole solidification process, the outset of solidification is delayed by Joule heat. And due to the accumulation of undercooling, dendrites suddenly nucleate, grow and finally become fine primary dendrite arm spacing. When ECP is imposed during the crystal growth stage only, the dendrites are remelted at first and then reappear along the original growing trajectories, showing the hereditary feature.
发表时间：2014-11-01