Observation of dendritic growth under the influence of forced convection


Observation of dendritic growth under the influence of forced convection

Roshchupkina, O.; Shevchenko, N.; Eckert, S.

The directional solidification of Ga–25wt%In alloys within a Hele-Shaw cell was visualized by X-ray radioscopy. The investigations are focused on the impact of melt convection on the dendritic growth. Natural convection occurs during a bottom up solidification because lighter solute is rejected during crystallization. Forced convection was produced by a specific electromagnetic pump. The direction of forced melt flow is almost horizontal at the solidification front. Melt flow induces various effects on grain morphology primarily caused by convective transport of solute, such as a facilitation of the growth of primary trunks or lateral branches, dendrite remelting, fragmentation or freckle formation depending on the dendrite orientation, the flow direction and intensity. Forced flow eliminates solutal plumes and damps local fluctuations of solute. A preferential growth of the secondary arms occurs at the upstream side of the dendrites, whereas high solute concentration at the downstream side inhibits the formation of secondary branches.

Keywords: X-ray radioscopy; in situ studies; melt convection; forced convection; dendritic growth

  • Open Access Logo Contribution to proceedings
    Modeling of Casting, Welding and Advanced Solidification Processes, 21.-26.06.2015, Awaji Yumebutai, Japan
    IOP Conference Series: Materials Science and Engineering 84(2015)1, 012080
    DOI: 10.1088/1757-899X/84/1/012080
    Cited 6 times in Scopus
  • Lecture (Conference)
    Modeling of Casting, Welding and Advanced Solidification Processes, 21.-26.06.2015, Awaji Yumebutai, Japan

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Publ.-Id: 21986