A gallium- 27 wt pct indium alloy is experimentally solidified in a square cavity, cooled from one vertical side wall. Solid, liquid, and mushy/slurry zones form during solidification. A thermosolutal convection pattern is inferred from the measured cooling curves, which also reveal undercooling and recalescence patterns. Two distinct recalescence patterns, one related to the nucleation and growth of the primary, indiumrich solid phase and the other associated with the precipitation of the secondary, gallium-rich solid phase, are observed. The sub-eutectic undercooling and subsequent nucleation of the secondary solid phase significantly affects the thermal behavior of the entire system and, thus, requires consideration in theoretical simulation models. Cooling curves also reveal the existence of two convection cells occupying top and bottom halves of the mold cavity, with slurry conditions prevailing during early stages of solidification, and it is concluded that the transport of dendrite fragments must be accounted for in numerical simulations.
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