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


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.


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


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  1. 1.
    Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperature, C 1421,Annual Book of ASTM Standards, ASTM, 1999Google Scholar
  2. 2.
    R. Damani, R. Gstrein, and R. Danzer, Critical Notch-Root Radius Effect in SENB-S Fracture Toughness Testing,J. Eur. Ceram. Soc., 1996,16, p 695–702CrossRefGoogle Scholar
  3. 3.
    S.S. Scherrer, I.L. Denry, and H.W.A. Wiskott, Comparison of Three Fracture Toughness Testing Techniques Using a Dental Glass and a Dental Ceramic,Dent. Mater., 1998,14, p 246–255CrossRefGoogle Scholar
  4. 4.
    G.D. Quinn, R.J. Gettings, and J.J. Kübler, Fractography and surface Crack in Flexure (SCF) Method for Evaluating Fracture Toughness of Ceramics,Fractography of Glasses and Ceramics III, Vol 64, J.R. Varner, V.C. Fréchette, and G.D. Quinn, Ed., American Ceramic Society, 1996, p 107–144Google Scholar
  5. 5.
    G. Gogotsi, Fracture Toughness Studies on Ceramics and Ceramic Particulate Composites at Different Temperatures,Fracture Resistance Testing of Monolithic and Composite Brittle Materials, ASTM STP 1409, J.A. Salem, G.D. Quinn, and M.G. Jenkins, Ed., ASTM International, 2002, p 199–212Google Scholar
  6. 6.
    G. Rausch, M. Kuntz, and G. Grathwohl, Determination of the in Situ Fiber Strength in Ceramic-Matrix Composites from Crack-Resistance Evaluation Using Single-Edge Notched-Beam Test,J. Am. Ceram. Soc., 2000,83(11), p 2762–2768CrossRefGoogle Scholar
  7. 7.
    Standard Test Method for Flexural Strength of Advanced Ceramics at Ambient Temperature, C 1161,Annual Book of ASTM Standards, ASTM, 1999Google Scholar
  8. 8.
    F.C. Peillon and F. Thevenot, Grain Coarsening in Gas Pressure Sintered Silicon Nitride,Ceram. Int., 2002,28, p 637–643CrossRefGoogle Scholar
  9. 9.
    S.J. Bennison, Crack-Resistance Behavior in Ceramics,Mechanical Testing Methodology for Ceramic Design and Reliability, D.C. Cranmer, and D.W. Richerson, Ed., Marcel Dekker, Inc., 1998, p 43–89Google Scholar
  10. 10.
    T. Nishida, Y. Hanaki, and G. Pezzotti, Effect of Notch-Root Radius on the Fracture Toughness of a Fine-Grained Alumina,J. Am. Ceram. Soc., 1994,77(2), p 606–608CrossRefGoogle Scholar
  11. 11.
    J.J. Kübler, Fracture Toughness of Ceramics using the SEVNB Method: From a Preliminary Study to a Test Method,Fracture Resistance Testing of Monolithic and Composite Brittle Materials, ASTM STP 1409, J.A. Salem, G.D. Quinn, and M.G. Jenkins, Ed., ASTM International, 2002, p 93–106Google Scholar
  12. 12.
    J. Kübler, Fracture Toughness of Ceramics Using The SEVNB Method: Initial Results for Si3N4 of a Joint Vamas/Esis Round Robin, CIMTEC World Ceramics Congress and Forum on New Materials, 1998 (Florence, Italy), Session C:L03Google Scholar
  13. 13.
    H. Awaji and Y. Sakaida, V-Notch Technique for Single-Edge Notched Beam and Chevron Notch Methods,J. Am. Ceram. Soc., 1990,73(11), p 3522–3523CrossRefGoogle Scholar
  14. 14.
    H. Kleebe, G. Pezzotti, and G. Ziegler, Microstructure and Fracture Toughness of Si3N4 Ceramics: Combined Roles of Grain Morphology and Secondary Phase Chemistry,J. Am. Ceram. Soc., 1999,82 (7), p 1857–1867CrossRefGoogle Scholar
  15. 15.
    G. Ziegler, J. Heinrich, and G. Wötting, Review: Relationships between Processing, Microstructure and Properties of Dense and Reaction-Bonded Silicon Nitride,J. Mater. Sci., 1987,22, p 3041–3086CrossRefGoogle Scholar
  16. 16.
    M. Poorteman, P. Descamps, F. Cambier, A. Poulet, and J.C. Descamps, Anisotropic Properties in Hot Pressed Silicon Nitride-Silicon Carbide Platelet Reinforced Composites,J. Eur. Ceram. Soc., 1999,19, p 2375–2379CrossRefGoogle Scholar
  17. 17.
    D. Park and C. Kim, Anisotropy of Silicon Nitride with Aligned Silicon Nitride Whiskers,J. Am. Ceram. Soc., 1999,82(3), p 780–782CrossRefGoogle Scholar
  18. 18.
    H. Imamura, K. Hirao, M.E. Brito, M. Toriyama, and S. Kanzaki, Further Improvement in Mechanical Properties of Highly Anisotropic Silicon Nitride Ceramics,J. Am. Ceram. Soc., 2000,83(3), p 495–500CrossRefGoogle Scholar
  19. 19.
    C.A. Costa, “Creep and Mechanical Behavior of Silicon Nitride Whiskers-Reinforced Silicon Nitride Composite Ceramics,” Ph.D. Thesis, Illinois Institute of Technology, 1996Google Scholar
  20. 20.
    R.W. Trice and J.W. Halloran, Mode I Fracture Toughness of a Small-Grained Silicon Nitride: Orientation, Temperature, and Crack Length Effects,J. Am. Ceram. Soc., 1999,82(3), p 2633–2640Google Scholar
  21. 21.
    A.K. Mukhopadhyay, S.K. Datta, and D. Chakraborty, Fracture Toughness of Structural Ceramics,Ceram. Int., 1999,25, p 447–454CrossRefGoogle Scholar

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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