Determination of the stability of Al11.8FeMn1.6Si1.6 phase existing in thequaternary Al-Fe-Mn-Si system

Using regular solution model the thermodynamic stability of the phase Al11. 8FeMn1.6Si1.6 was assessed in the temperature range 878-973 K. In order to calculate activities of components in the liquid phase remaining in equilib rium with the solid phase, experimentally determined liquidus composition w ere used together with literature data available for respective binary syst ems. It was assumed that in the limited range of concentrations thermodynam ic properties of binary liquid solutions obey regular solution behaviour. T emperature dependence of the G i b b s free energy change derived for the r eaction of formation of the Al11.8FeMn1.6Si1.6 phase using regular solution model takes the form: Delta G(o) = - 416.7 + 0.0654 . T kJ/mol.