Research Progress in Measurement of Atomic Diffusivity in Alloy Melts under High Magnetic Field

Author of the article:LIN Wenhao1,2, CAI Hao1,2, LIU Ying1,2, ZHOU Bangfei1,2, ZHENG Tianxiang1,2, ZHONG Yunbo1,2

Author's Workplace：1. State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200444, China; 2. School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China

Key Words：liquid alloy; diffusion coefficient; melt convection; high static magnetic field

Abstract：The accurate measurement of the diffusion coefficient of alloy melt is helpful to understand the atomic structure of metal melt and the physical nature of atomic migration, which provides experimental basis for the research of atomic diffusion mechanism and physical model establishment of liquid metal and subsequent material design. Accurate measurement of diffusivity in alloy melts remains a challenge due to the inevitable presence of multiple types of flows. In this paper, several measurement techniques for diffusivity of alloy melt are reviewed, including long capillary tube technique, capillary-molten pool technique, shear element technique, sliding shear technique, X-ray imaging technique and gravity assisted automatic docking technique. The measurement of diffusion coefficient using the above technology in the ground was analyzed, microgravity and strong static magnetic field, and compares the advantages and disadvantages of the current measurement technology. By means of gravity assisted automatic docking device, the diffusion coefficient of up to 22 T strong static magnetic field is measured. The strong static magnetic field can effectively suppress the melt convection, and the diffusivity values are comparable to those measured in microgravity field. It is possible to use the MHD effect of strong static magnetic field to create a pure diffusion measurement environment and further improve the accuracy of diffusion coefficient measurement.