An opposite trend for collision intensity of minor-phase globules within an immiscible alloy droplet

Collision behaviors of minor-phase globule were investigated in SCN-60 wt%H2O mixture under an annular temperature gradient, and during its migration the trend for collision intensity was determined experimentally. It was found that the collision intensity became stronger and stronger when the globules migrated from the sample edge to its center, which was opposite to the previous calculation. Our results have showed that although the radius of minor-phase globule increased by collision and subsequently made a positive contribution to the velocity, the actual velocity was still reduced. This demonstrated that the velocity was dominantly controlled by temperature gradient, rather than the globule's radius. It was also found that the growth rate of globule radius was increasing with time, indicating that the collision became more frequent and its intensity increased from the sample's edge to its center. In addition, this finding was examined by Fe-58 wt%Sn immiscible alloy using drop tube processing, and the solidified microstructure agreed well with the observation result. Our findings provided an in-depth understanding to the collision-induced assembly of minor-phase globules inside an immiscible alloy droplet. (C) 2019 Elsevier B.V. All rights reserved.