The adiabatic drop-calorimetry method is applied in the temperature range from 400 to 1100 K to measure the enthalpy increment ΔHb(T) of polycomponent aluminum alloys 2007, 2011, 6012, and 6082 relative to the "reference" temperature Tb = 293.15 K. The experimental dependences for all alloys are well described by the calculated curves. The basic thermodynamic characteristics of the alloys in the melting region are determined.