Journal of Materials Engineering and Performance

, Volume 15, Issue 5, pp 591–595 | Cite as

Effect of notch-root radius on the fracture toughness of composite Si3N4 ceramics

  • Cláudio Vasconcelos Rocha
  • Célio Albano da Costa
Article

Abstract

In-situ silicon nitride and a whisker-reinforced silicon nitride-silicon nitride composite, densified via gas pressure sintering and hot pressing, respectively, were evaluated using the single-edge V-notched beam (SEVNB) fracture toughness technique. The mean value ofK IC for each material was 5.7 and 7.9 MPa·m1/2, respectively, and the toughness was influenced by the presence of the elongated Si3N4 grains in the microstructure. The notch radius was observed to have the same effect as a sharp crack when notch-root radius was smaller than 10 µm, which was considered to be a realK IC for these materials.

Keywords

fracture toughness gas pressure sintering hot pressing notch-root silicon nitride 

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Copyright information

© ASM International 2006

Authors and Affiliations

  • Cláudio Vasconcelos Rocha
    • 1
  • Célio Albano da Costa
    • 1
  1. 1.Programa de Engenharia Metalúrgica e de Materiais (PEMM/COPPE), Centro de TecnologiaUniversidade Federal do Rio de JaneiroRio de JaneiroBrazil

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