Effect of Zr addition on the mechanical properties of Nb Si based alloys

Abstract In the present study, the effect of Zr addition on the mechanical properties of arc melted hypoeutectic Nb−16 at. %Si alloy has been investigated. The alloys were characterized by scanning electron microscopy (SEM), electron back scattered diffraction (EBSD), hardness test, nanoindentation test, compression test and three point bend test. The desirable phase α−Nb 5 Si 3 phase could be obtained in alloys containing 4 at. % or more Zr. Nanoindentation results showed that the elastic modulus of Nb ss phase is not significantly influenced by Zr additions whereas elastic modulus of Nb 3 Si and α−Nb 5 Si 3 phases are considerably improved by Zr additions. The strength, plasticity and room temperature fracture toughness of the alloys are significantly increased with Zr addition. The maximum compressive strength of 2160 ± 80 MPa, plastic strain of 2.6 ± 0.2% and fracture toughness of 14.3 ± 0.3MPam 1/2 are achieved in alloy with 4 at.% Zr.