TY - CONF

T1 - On the conditions for the occurrence of crystal avalanches during alloy solidification

AU - Siyahatshayesteh, Golshan

AU - Ludwig, Andreas

AU - Stefan-Kharicha, Mihaela

AU - Wu, Menghuai

AU - Kharicha, Abdellah

PY - 2024/6

Y1 - 2024/6

N2 - Experimental studies on the solidification of ammonium-chloride-water alloys in rel-atively large containments reveal conditions that lead to the formation of numerous crystal ava-lanches. Columnar segments that occasionally slide downwards along a vertical mushy zonefurther fragmentate and so crystal multiplication occurs. As a condition for this phenomenonsolidification-induced solutal buoyancy that leads to a rising interdendritic flow was identifiedfor the present case. The interaction with sedimentation-induced downward flow ahead of a ver-tical columnar region results in a redirection of the interdendritic flow and thus, to local condi-tions that slow down further solidification or even lead to remelting. Gravity is then pulling loosesegments downwards. In larger containment, the flow in the bulk melt is generally unsteady andeven turbulent. Thus, the outlined flow-solidification/melting interplay happens frequently atnumerous positions but in a stochastic manner.

AB - Experimental studies on the solidification of ammonium-chloride-water alloys in rel-atively large containments reveal conditions that lead to the formation of numerous crystal ava-lanches. Columnar segments that occasionally slide downwards along a vertical mushy zonefurther fragmentate and so crystal multiplication occurs. As a condition for this phenomenonsolidification-induced solutal buoyancy that leads to a rising interdendritic flow was identifiedfor the present case. The interaction with sedimentation-induced downward flow ahead of a ver-tical columnar region results in a redirection of the interdendritic flow and thus, to local condi-tions that slow down further solidification or even lead to remelting. Gravity is then pulling loosesegments downwards. In larger containment, the flow in the bulk melt is generally unsteady andeven turbulent. Thus, the outlined flow-solidification/melting interplay happens frequently atnumerous positions but in a stochastic manner.

KW - crystal avalanches

KW - solidification

KW - ammonium-chloride-water

U2 - 10.1088/1742-6596/2766/1/012199

DO - 10.1088/1742-6596/2766/1/012199

M3 - Paper

T2 - 9th edition of the European Thermal Sciences Conference

Y2 - 10 June 2024 through 13 June 2024

ER -