Journal of the Korean Ceramic Society (한국세라믹학회지)

The Korean Ceramic Society (한국세라믹학회)
권호 표지

Effects of the Residual Stress on Fracture Toughness in ZTA

ZTA에서 잔류응력이 파괴인성 증진에 미치는 영향

  • Lee, Young-Min (Department of Materials Science & Engineering, KAIST) ;
  • Yu, Jin (Department of Materials Science & Engineering, KAIST)
  • 이영민 (한국과학기술원 재료공학과) ;
  • 유진 (한국과학기술원 재료공학과)
  • Published : 1990.03.01
Download PDF
⟨ Previous Next ⟩

Abstract

In this investigation, bar-shaped specimens which consisted of three layers are prepared to study the effects of residual compressive stress on the mechanical properties in ZTA. The outer layers contained Al2O3 and unstabilized ZrO2 and the central layer contained Al2O3 and stabilized ZrO2(with 5.10wt% Y2O3). When cooled from the sintering temperature, some of zirconia in the outer layers transformed to the monoclinic form while zirconia in the central layer was retained in the tetragonal form. The transformation which induces to dilatational expansion led to the estabilishmenet of compressive stress in the outer layers and balances tensile stress in the central layer. Decrease of outer layer thickness(for a fixed total thickness)increases residual compressive stress. Because of residual compressive stress in the outer layers, the fracture toughness of outer layers of 3-layers composite is 10.21 Mpam1/2, which is increased to 25% above in comparison with 1-layer specimens in ZTA. Also, the 3-layers composite is believed to exhibite greater fracture resistance in contact damage environment from thermal shock test.

Keywords

References

  1. J. Am. Cer. Soc. v.51 no.2 Strengthening Glass-Ceramics by Application of Compressive Glazes D.A. Duke;J.E. Megles;J.E. MacMowell;H.E. Bopp
  2. U.S. Pat. No. 3911 v.188 High Strength Composite Structure M.L. Torti, Jr.;D.W. Richerson
  3. J. Mater. Sci. v.20 The Effect of Binder Thickness and Residual Stresses on the Fracture Toughness of Cemented Carbides R.A. Cutler;A.V. Virkar
  4. Ceramic Microstructures'76 Surface Strengthening of Transformation Toughened Zirconia R.T. Pascoe;R.C. Garvie
  5. Mater. Res. Bull. v.12 no.10 Effect of Grinding and Polishing on Near Surface Phase Transformations in Zirconia J.S. Reed;A. Lejus
  6. J. Am. Cer. Soc. v.70 no.3 Strengthening of Oxide Ceramics by Transformation-Induced Stresses A. Virkar;J.L. Huang;R.A. Cuttler
  7. Int. J. Sol. Struc. v.19 no.4 Continuum Theory of Dilatant Transformation Toughening in Ceramics B. Budiansky;J.W. Hutchinson;Lambropolous
  8. J. Am. Cer. Soc. v.66 no.10 A Technique of Introducing Surface Compression into Zirconia Ceramics D.J. Green
  9. Advances in Ceramics;Am. Cer. Soc. v.12 Residual Surface Stresses in Al₂O₃-ZrO₂Composites D.J. Green;J. Amer. Cer. Soc.
  10. J. Am. Cer. Soc. v.65 no.5 Influence of MgO Addition on the Microstructure and Mechanical Properties of Al₂O₃-ZrO₂Composites Tomas Kosmac
  11. J. Am. Cer. Soc. v.55 no.1 Phase Analysis in Zirconia Systems R.C. Garvie;P.S. Nicholson
  12. J. Mat. Sci. v.10 Equilibrium Penny-like Cracks in Indentation Fracture B.R. Lawn;E.R. Fuller
  13. ASTM STP 839 McCall;Steele
  14. J. Am. Cer. Soc. v.63 no.3-4 Sintering of Si₃N₄-Y₂O₃-Al₂O₃ Ronald E. Loehman;David T. Rowcliffe
  15. Acta Metall. v.35 no.11 Microcrack Toughening in Alumina/Zirconia M. Ruhle;A.G. Evans;R.M. McMeecking;P.G. Charalambides;J.W. Hutchinson
  16. J. Am. Cer. Soc. v.59 Fracture Toughness of Alumina with Unstabilized Zirconia Dispersed Phase N. Claussen
  17. J. Am. Cer. Soc. v.65 no.5 Mechanics of Transformation Toughening in Brittle Solids R.M. McMeeking;A.G. Evans
  18. Acta Metall. v.35 no.7 Crack Tip Shielding by Micro-Cracking in Brittle Solids J.W. Hutchinson
  19. Acta Metall. v.31 no.4 Crack Deflection Processes-I. Theory K.T. Faber;A.G. Evans