Liquid phase separation of ternary Al-In-Sn/Ge monotectic type alloys investigated with calorimetric method

The phase equilibrium, thermodynamic properties and liquid demixing patterns for binary Al_100-xIn_x, ternary (Al_100-xIn_x)₉₀Sn₁₀ and (Al_100-xIn_x)₉₀Ge₁₀ (x = wt.%) alloys are investigated by differential scanning calorimetry (DSC) method. The corresponding phase diagrams are experimentally established, and it is found that both monotectic temperature and critical temperature for immiscibility gap decrease when either Sn or Ge is added to binary Al_100-xIn_x alloys. The enthalpy of fusion for binary Al-In alloys, ternary Al-In-Sn and Al-In-Ge alloys shows linear functions with In content, and the introduction of Sn and Ge elements decreases the enthalpy of fusion. The liquid phase separation mechanism is discussed in relation to the DSC curves and solidified microstructures. It is demonstrated that the core and shell phases can be altered by the addition of Ge element in (Al_100-xIn_x)₉₀Ge₁₀ alloys as compared with those in binary Al_100-xIn_x and ternary (Al_100-xIn_x)₉₀Sn₁₀ alloys. This provides an effective way to switch the inner and outer phases for core-shell structure.