Effects of element addition on liquid phase separation of Bi-Ga immiscible alloy: Characterization by electrical resistivity and coordination tendency

Abstract The application of immiscible alloys is limited by their macrosegregation caused by liquid phase separation upon solidification. So liquid phase separation tendency is the primary factor should be concerned in the design of an immiscible alloy. In present work, the effects of tin and indium additions on liquid phase separation of Bi 33.3 Ga 66.7 (at.%) immiscible alloy were studied by electrical resistivity measurement. It is observed that the liquid phase separation tendency of Bi 33.3 Ga 66.7 alloy is weakened by tin but enhanced by indium addition within a minor quantity. Based on thermodynamic calculations, the effects of element additions on liquid phase separation of immiscible alloy were understood in the viewpoint of coordination tendency between elements: liquid phase separation tendency of immiscible alloy is weakened by the element addition which presents homo-coordination tendency with both the constituent elements of the immiscible alloy in liquid state; liquid phase separation tendency is enhanced by the element addition which presents hetero-coordination tendency with one of the constituent elements of the immiscible alloy but homo-coordination tendency with the other in liquid state.