In situ observation of directional solidification in Ga-In alloy under a transverse DC magnetic field


In situ observation of directional solidification in Ga-In alloy under a transverse DC magnetic field

He, S.; Shevchenko, N.; Eckert, S.

The directional solidification of a Ga-25wt.%In alloy under the effect of a transverse DC magnetic field is investigated by X-ray radiography. The magnetic field pointing parallel to the X-ray beam is generated by two ring-shaped permanent magnets. The magnetic field reaches values up to ~0.19 T in the field of view. The dendritic growth and the flow patterns of Ga-rich plumes migrating along the solidification front are captured and analyzed. It shows that the local fluctuations of solute concentration are partially damped by the magnetic field. At the temperature gradient of 1 K/mm, the growth velocities of solidification front and plumes are not affected. In the case of higher temperature gradient (~2 K/mm), the magnetic field causes an increase of the plume velocity in the horizontal direction and a decrease in the vertical direction while the velocity of the solidification front remains constant. Additionally, it is found that the magnetic field damps the fluctuations of tip velocity and refines the primary arm spacing. Above phenomena are discussed based on the thermoelectric magnetic and electromagnetic braking effects. The in situ experimental data are important for verification and improvement of the existing numerical simulations of solidification under the magnetic field.

Keywords: X-ray radiography; directional solidification; transverse magnetic field; dendritic growth; Ga-rich plumes

  • Poster (Online presentation)
    MCWASP XV: Modelling of Casting, Welding and Advanced Solidification Processes, 22.-23.06.2020, Jönköping, Sweden
  • Open Access Logo IOP Conference Series: Materials Science and Engineering 861(2020)1, 012025
    DOI: 10.1088/1757-899X/861/1/012025
    Cited 3 times in Scopus

Permalink: https://www.hzdr.de/publications/Publ-31072
Publ.-Id: 31072