Partial for gadolinium and integral enthalpies of mixing were determined for liquid Al-Ga-Gd alloys using a high-temperature isoperibolic calorimeter at 1760 5 K. The experiments were performed along five sections with constant concentration ratios of Al and Ga in a range of 0.0 less than or equal to x(Gd) less than or equal to 0.6. The resulted integral enthalpies of mixing were fitted by polynomial concentration dependences. The deviation between experimental and predicted by geometric model values of integral enthalpy of mixing was found to be 5.25%, so ternary interaction is negligibly small at the experimental temperature. It has been determined that ternary alloys thermodynamics is preferentially defined by influence of congruently melting binary GaAl2 and GdGa2 intermetallides. (C) 2004 Elsevier B.V. All rights reserved.