Composite materials show attractive properties resulting From the combination of properties of their constituent phases. Special interest has been devoted to the intermetallic matrix composites, since they have been recognized as potential substitutes for the superalloys. An interesting and efficient means of preparation of the composite materials is the directional solidification of eutectic alloys. The eutectic microstructure of many systems possesses inherent thermal stability and may result in a composite material, with an aligned, finely dispersed microstructure. The goal of this study was to evaluate the influence of a ternary element addition (Cu, Si, Ni, Ti and Cr) on the microstructure of the Al-Nb eutectic system. Microstructural characterization of the as-cast and directionally solidified samples, revealed changes in the eutectic morphology from cellular to dendritic and from lamellar to rod or globular structure. Also, it was confirmed that the alloy containing 57.18% Al-40.40% Nb-2.42% Ni in atomic% exhibits a ternary eutectic reaction. The directional solidification of this alloy resulted in a regular three-phase eutectic microstructure.