TY - CONF

T1 - Flow-enhanced remelting of settling/floating globular crystals during mixed columnar-equiaxed solidification

AU - Wu, Menghuai

AU - Zhang, Zhao

AU - Ludwig, Andreas

AU - Kharicha, Abdellah

N1 - The authors acknowledge the financial support from the Austrian Research Promotion Agency (FFG) through the project Bridge I (No. 868070) and the Austrian Science Fund in the framework of the FWF- NKFIN joint project (FWF, I 4278-N36).

PY - 2023

Y1 - 2023

N2 - Previously, the authors have used a mixed columnar-equiaxed solidification model, suc-cessfully ‘reproduced’ the solidification benchmark experiments on the Sn-10wt.%Pb alloy undernatural/forced convections (travelling magnetic stirring) as performed at SIMAP laboratory [Int. J.Heat Mass Transf. 85 (2015) 438-54]. The current contribution is to address the flow-effect on theremelting of settling/floating crystals during the mixed columnar-equiaxed solidification. The re-melting or growth is controlled by diffusion of solute in the liquid boundary layer. The diffusionlength due to the flow-effect is modelled as a function of Schmidt and Reynolds numbers. The mod-elling results show that remelting rate of the floating/settling crystals, which originate from fragmen-tation and then brought to the superheated region by the forced flow, can be enhanced by the flow.In turn the released latent heat can reduce the temperature locally (even globally), hence to speed upthe solidification of the columnar structure. Additionally, the solidification-migration-remelting ofequiaxed grains present an important macrosegregation mechanism. By solidification of a crystal inthe cold region it rejects solute, while by remelting of the crystal it dilutes the surrounding melt.These phenomena are found critical in many engineering castings with mixed columnar-equiaxedsolidification.

AB - Previously, the authors have used a mixed columnar-equiaxed solidification model, suc-cessfully ‘reproduced’ the solidification benchmark experiments on the Sn-10wt.%Pb alloy undernatural/forced convections (travelling magnetic stirring) as performed at SIMAP laboratory [Int. J.Heat Mass Transf. 85 (2015) 438-54]. The current contribution is to address the flow-effect on theremelting of settling/floating crystals during the mixed columnar-equiaxed solidification. The re-melting or growth is controlled by diffusion of solute in the liquid boundary layer. The diffusionlength due to the flow-effect is modelled as a function of Schmidt and Reynolds numbers. The mod-elling results show that remelting rate of the floating/settling crystals, which originate from fragmen-tation and then brought to the superheated region by the forced flow, can be enhanced by the flow.In turn the released latent heat can reduce the temperature locally (even globally), hence to speed upthe solidification of the columnar structure. Additionally, the solidification-migration-remelting ofequiaxed grains present an important macrosegregation mechanism. By solidification of a crystal inthe cold region it rejects solute, while by remelting of the crystal it dilutes the surrounding melt.These phenomena are found critical in many engineering castings with mixed columnar-equiaxedsolidification.

KW - Flow-enhanced remelting

KW - mixed columnar-equiaxed solidification

KW - settling/floating globular crystals

U2 - 10.1088/1757-899X/1281/1/012036

DO - 10.1088/1757-899X/1281/1/012036

M3 - Paper

T2 - MCWASP XVI IOP Conf. Series: Materials Science and Engineering

Y2 - 18 June 2023 through 23 June 2023

ER -