The results of the study of the structure and distribution of chemical elements in high-entropy alloys (HEA) of Al$_{x}$FeNiCoCuCr system (x = 1, 1.5, 1.8) are presented. Investigations are carried out by X-ray, metallographic, and electron microscopy analyses using capabilities of the energy dispersive analysis. Mechanical properties are determined by the hardness and microhardness measurements. As found, the HEA consist of b.c.c. and f.c.c. phases. Furthermore, the alloy with equiatomic composition contains two f.c.c. phases with high copper content and different lattice parameters. Inhomogeneous distribution of Cu is found between dendrites and other phases at a relatively homogeneous distribution of other chemical elements. As shown, both the formation of structure in different areas of ingot section and the transition from grain structure to dendritic one depend on the cooling rate determined by the distance from contact surface of a hearth. As revealed, the dispersion of structural elements of the HEA increases with aluminium content growing. As shown, at the cooling, the decomposition of copper-depleted solid solution (inside the grains and dendrites) is accompanied by formation of ordered disperse precipitates of lamellar shape.