Effects of High Magnetic Field on the Growth Rate and Characteristic Size of Succinonitrile Dendrites

Author of the article:CHEN Zijian1 , LI Jie1 , YAN Yujie1 , LI Chao1,2, ZHANG Pingxiang1,3, WANG Jun1

Author's Workplace：1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China; 2. Xi'an Superconducting Magnet Technology Co., Ltd., Xi'an 710018, China; 3. Northwest Institute for Nonferrous Metal Research, Xi'an 710016, China

Key Words：high magnetic field; succinonitrile; directional solidification; dendrite growth rate; characteristic size

Abstract：The transparent metalloid organic compound succinonitrile (SCN) was used as the research object in this paper, and the changes of microstructure of SCN during directional solidification with or without high magnetic field were studied by in-situ observation. During the experiment, the self-made in-situ observation directional solidification device was used to conduct directional solidification of SCN with 0 and 3 T magnetic field, and three temperature gradients (5, 10, 15 K/mm) were set. The process of directional solidification was photographed and recorded with an optical microscope, revealing the influence mechanism of high magnetic field on the directional process of SCN. The results show that the dendrite morphology of SCN is oblique dendrite without magnetic field. With the increase of temperature gradient, the growth rate of dendrites increases, the dendrite tile angle decreases, the dendrite tip radius decreases, and the primary and secondary dendrite arm spacing decreases; after applying 3 T magnetic field, it is found that the dendrite-to-cell transition occurs under the same temperature gradient, the growth rate of dendrites slows down, the dendrite tile angle increases, the dendrite tip radius increases, and the primary and secondary dendrite spacing increases.