Liquid–liquid phase equilibrium and core–shell structure formation in immiscible Al–Bi–Sn alloys

In this paper, the liquid-phase separation of ternary immiscible Al45Bi19.8Sn35.2 and Al60Bi14.4Sn25.6 melts was studied with resistivity and thermal analysis methods at different temperature. The resistivity–temperature curves appear abrupt and anomalously change with rising temperature, corresponding to the anomalous and low peak of melting process in DSC curves, indicative of the occurrence of the liquid-phase separation. The anomalous behavior of the resistivity temperature dependence is attributable to concentration–concentration fluctuations. The effect of composition and melt temperature on the liquid-phase separation and core–shell structure formation in immiscible Al–Bi–Sn alloys was studied. The liquid-phase separation and formation of the core–shell structure in immiscible Al–Bi–Sn alloys are readily acquired when the alloy compositions fall into liquid miscibility gap. What’s more, the cross-sectional structure changes from irregular, dispersed to core-type shapes under the actions of Marangoni motion with increasing melt temperature. This study provides some clues for the preparation of core–shell microspheres of immiscible Al–Bi–Sn alloys via liquid-phase separation.