Six alloys of the Al-Cu-Ti-Fe system are smelted. The alloys’ composition varies in the following ranges [wt.%]: 5.1-6.1% Cu, 0.05-0.32% Ti, 0.06-0.19% Fe. The alloys are investigated in the liquid state by the high-temperature x-ray diffraction method in a helium environment at 700°С and 1000°С. Structure factors and pair distribution functions are calculated from the measured scattering curves. In turn, the numbers of atoms in the first co-ordination sphere (co-ordination numbers) are determined from the pair-distribution curves. Models of the melt structure are designed using the inverse Monte Carlo method in such a way to correspond maximally to experimentally determined structure-factor curves. Partial structure factors and pair distribution functions for Al-Al, Al-Cu and Al-Ti atomic pairs as well as co-ordination numbers for atoms of different kinds are calculated from the obtained models. The constructed models are divided into Delaunay simplexes, and polytetrahedral atomic clusters of the icosahedral type are defined. It is determined that the copper content in such clusters is 3-4 times higher than in the homogeneous melt.