<p>The phase composition, microstructure and properties of laser melting deposited Nb–16Si–22Ti–3Al alloys with different TaB₂ (0, 0.25, 0.5, 1.0, 2.0 at%) additions were studied. The results showed that the microstructure of Nb–16Si–22Ti–3Al alloy without TaB₂ was mainly composed of Nbss phase, Nbss/Nb₃Si eutectic and a small amount of α-Nb₅Si₃ phase. With the TaB₂ addtion increased, the Nbss/Nb₃Si eutectic in the alloy gradually diminished and Nbss + (α,γ)-Nb₅Si₃ eutectic structure were found. Compared to the untreated condition, when 0.25 at% TaB₂ was added, the Nbss content in the alloy sample increased from 50.2 to 56.2 vol%, the Nb₃Si content decreased from 36.7 to 14.2 vol%, the α-Nb₅Si₃ content rose from 12.1 to 23.7 vol%, and the γ-Nb₅Si₃ phase emerged (5.2 vol%). The average fracture toughness of 0.25 at% TaB₂ alloy was the best among all samples, reaching up to 13.1&#xa0;MPa·m^1/2. The reasons for this were attributed to the refinement of the microstructure and the increase in the content of the ductile phase (56.2 vol%) together with the decomposition of Nb₃Si into Nb + Nb₅Si₃. The microhardness and compressive strength of the alloy both increased continuously with the addition of TaB₂, reaching the maximum values up to 615.3 HV_0.2 and 2053&#xa0;MPa, respectively for the alloy with 2.0 at% TaB₂ addtion. The reason for this were the increase in volume fraction and the growth of the silicide phase in the alloy.</p> Graphical Abstract <p></p>