This work investigates the influence of small additions of aluminum on the structure of ingots from a high-entropy alloy of the (Fe0.25Co0.25Ni0.25Cr0.125V0.125)83B17 composition. The structure of experimental alloys was analyzed using scanning electron microscopy and EDX analysis. The borides formed in the structure were analyzed by transmission electron microscopy, X‑ray diffraction, and electron backscatter diffraction. Aluminum addition was found to change the crystallization process of the alloys, affecting the type of primary boride crystals and eutectic composition. The addition of aluminum to the alloy in greater amounts changes the boride type from refractory boride of (V, Cr)B type to a more easily melting type of boride M3B2.