Effect of W Alloying and NbC Dispersion on High Temperature Strength at 1773 K and Room Temperature Fracture Toughness in Nb<SUB>5</SUB>Si<SUB>3</SUB>/Nb <I>In-situ</I> Composites

  • Kim Won-Yong
    Japan Ultra-High Temperature Materials Research Institute(JUTEM)
  • Tanaka Hisao
    Japan Ultra-High Temperature Materials Research Institute(JUTEM)
  • Hanada Shuji
    Institute for Materials Research, Tohoku University

Bibliographic Information

Other Title
  • Effect of W Alloying and NbC Dispersion on High Temperature Strength at 1773K and Room Temperature Fracture Toughness in Nb5Si3/Nb In-situ Composites

Search this article

Abstract

The effects of W alloying and NbC dispersion on high temperature strength at 1773 K and room temperature fracture toughness are investigated using Nbss/Nb5Si3 and Nbss/Nb5Si3/NbC in-situ composites with the hypoeutectic composition, where Nbss denotes Nb solid solution. With increasing W content, 0.2% offset yield stress for both composites increases at 1773 K. The increase in the yield strength is attributable to the solid solution strengthening in Nbss by adding W, low diffusivity of W in Nbss and microstructural change caused by W addition. With increasing W content, fracture toughness decreases in the Nbss/Nb5Si3, but no marked change is observed in the Nbss/Nb5Si3/NbC. A crack propagates straightly in Nb–16Si–5Mo–15W, while crack deflection and branching take place in the Nbss/Nb5Si3/NbC. Fractography reveals that Nbss/Nb5Si3 fractures completely in a transgranular mode, while Nbss/Nb5Si3/NbC fractured in a mixed mode of transgranular fracture and interface decohesion between NbC and Nbss or Nb5Si3 and Nbss. It is suggested that the presence of NbC dispersoids in Nbss/Nb5Si3 is effective to increase high temperature strength without a significant decrease of fracture toughness.

Journal

  • MATERIALS TRANSACTIONS

    MATERIALS TRANSACTIONS 43 (6), 1415-1418, 2002

    The Japan Institute of Metals and Materials

Citations (2)*help

See more

References(27)*help

See more

Details

Report a problem

Back to top