The Influence of Production Technology on the Structure and Mechanical Properties of Niobium–Silicon–Aluminum Alloys

Cast Nb–14 at % Si–9 at % Al alloys fabricated by self-propagating high-temperature synthesis (SHS) and by SHS followed by electric arc remelting have been investigated. A structure consisting of a solid solution of silicon and aluminum in niobium (NbSS), a Nb3Al intermetallic compound, and a β-Nb5(Si,Al)3 silicide formed in the alloy fabricated by SHS. Electric arc remelting suppressed the formation of the Nb3Al phase and resulted in the formation of a dispersed two-phase NbSS and β-Nb5(Si, Al)3 structure in the alloy. The increased volume fraction of NbSS and the dispersed structure formed after electric arc remelting in the alloy increase its fracture toughness to 14.8 ± 0.8 MPa m1/2 compared to 7.7 ± 0.8 MPa m1/2 for the SHS-prepared alloy.