512 A.K. Ray, E. R. Fuller, S. Banerjee from the precracked four-point bend speci 13. Becher, P. F.& Wei, G. C, Toughening behaviour in mens were higher and had a value given by C-whisker-reinforced alumina. Am. Ceram. Soc K1c=596±0l5MPam12 67(12)(1984)267-9 14. Wei, G. C& becher, P F, Development of Sic whi (2)The 25 wt% silicon carbide whisker rein reinforced ceramics. J. Am. Ceram. Soc. Bull hiskey forced alumina ceramic composite is suscep 1985)298-304 tible to a fatigue crack growth phenomenon 15. Ray, A.K.& banerjee hich is similar to that observed in the case of metallic materials. But the crack growth exponent is higher(n =15.5) 16. Brown Jr, w. F& Srawley, J. E, in ASTM STP (3) At low AK fatigue(0-8 to 1-8 MPa m ), the American Society for Testing and Materials, phila hia. PA. 1966 whiskers failed by fatigue, whereas during 17 Yamade, Y.& Kishi, T, Acoustic emission study for monotonic fracture, they failed by pull-out. fracture origin of sintered mullite in 4-point bending test (4)The matrix at low AK fatigue was predomi The Sumitomo Search, 45(3) (1991)17-24 18. Anstis, G. R, Chantikul, P, Lawn, B. R.& marshall nantly transgranular with frequent crack D. B, A critical evaluation of indentation techniques branching and deflection, in contrast to a measuring fracture toughness: I direct crack measurement J. Am. Ceram Soc 64(1981)533-8 mixed mode type (45% transgranular and 9. vickers indentation, fracture toughness on the surface 55%/ intergranular) failure during the mono- Ponton, C. B.& Rawlings, R. D, Dependence of the tonic fracture crack length. Br. Ceram. Trans. J, 88(1989)83-90 20. Dauskardt, R. H, Marshall, D. B. Ritchie, R.O. yclic fatigue-crack propagation in magnesia-partiall stabilized zirconia ceramics. Am. Ceram. Sc Reference 21. Tsai, J. F, Yu, C.S.& Shetty, D. K,, Fatigue crack I. Becher, P, F, Such, C. H, Angelini, P. Tiegs, T. N propagation in ceria-partially stabilized zirconia( Ce-TZPH Toughening behaviour in whisker-reinforced ceramic matrix alumina composites. J, Am. Ceram. Soc., 73(10)(1990) composites. J. Am. Ceram. Soc., 71(12)(1988)1050-61 2992-3001. 2. Becher, P. F, Microstructural design of toughened 22. Dauskardt, R. H, James, M.R., Porter, J. R& Ritchie ceramics. J. Am. Ceram Soc., 72(2)(1991)255-69 R.O., Cyclic fatigue crack growth in a SiC whisker-rein 3. Becher, P. F.& Tiegs, T. N, Toughening behaviour forced alumina ceramic composite: long and small crack involving multiple mechanisms: whisker reinforcement behaviour. J. Am. Ceram. Soc, 75(4)(1992)759-71 and zirconia toughening. J. 4m. Ceram. Soc., 70(9) 23. Lange, F. F, James, M.R.&Green,DJ,Determina (1987)6514 tion of residual stresses caused by grinding in polycrys- 4. Angelini, P, Mader, w.& becher, P F, Strain and frac- talline Al,O3. J. Am. Ceram. Soc., 66(1983)C-16 ture in whisker reinforced ceramics In MRS Proceedings 24. Cook, R F, Lawn, BR, Dabbs, T P& Chantikul Vol. 78, Advanced Structural Ceramics. ed. P. F. Becher Effect of machining damage on the strength of a glass M. v Swain and S. Somuja Materials Research Socicty, ceramic. J. Arm. Cerum. Soc., 64 (1981)C-121-2. Pittsburgh, PA, 1987, pp. 241-57 25. Green, D J, Lange, F. F.& James, M.R., Factors infl. 5. Ruhle. M. Dalgeish. Evans. A G. On the toughen uencing residual surface stresses due to a stress-induced ing of ceramics by whiskers. Scr. Metall, 21 ( 1987)681-6 phase transformation. J. Am. Ceram Soc, 66(1983)6239 6. Warren. R. Sarin. V. K. fracture of whisker rein- B. R. An indentation tech forced ceramics. In Application of fracture Mechanics to nique for measuring stresses in tempered glass-surfaces Composite Materials, ed. K. Friedrich. Elsevier, Amster Am. Ceram.Soc,60(1977)86-7 27. Ikuma. Y.& Virkar, A 7. Krause Jr,R. F.& Fuller Jr, E.R., Fracture toughness fracture toughness in transformation-toughened ceramics behaviour of a silicon carbide whisker reinforced alumina J. Mater.Sci,19(1984)223-8 with selected properties. In Proc. the Fossil Energy Mate- 28. Bhattacharya, A. K.& Petrovic, J, J, Hardness and frac rials Conference, Report No. ORNL/FMP/87/G, Martin ture toughness of SiC-particle-reinforced MoSi, composite Marietta Encrgy Systcms, Inc, Oak Ridge National Lab- J.Am. Ceram.Soc…,7410)(1991)2700-3 oratory, TN, USA, August 1987, pp 38-55 29. Swanson, P. L, Fairbanks, C. J, Lawn, B. R. Mai 8. Krause Jr, R. F, Fuller Jr, E. R. rhodes, J. F, frac Y.w.& Hockey, B J, Crack-interface grain bridging as ure resistance behaviour of silicon carbide whisker-rein- a fracture resistance mechanism in ceramics: 1, experiment forced alumina composites with different poros study in alumina. J. Am. Ceram Soc., 70(4)(1987)279 Am. Cerum.Soc,73(3)(1990)55966 30. Ramchandran, N. Shetty, D. K, Rising crack growth 9. Campbell, G. H, Ruhle, M, Dalgleish B. J. Evans, A.G resistance(R-curve)behaviour of toughened alumina and Whisker toughening: a comparision between AL, O, and licon nitride. J. Am. Ceram. Soc., 74(10)(1991)2634-41 Si3N4 toughened with silicon carbide. J. Am. Ceram. 31. Anderson, R. M.& Braun, L. M, Technique for the Soc,733)(1990)521-30. R-curve determination of Y-TZP using indentation-pro- 10. St anical properties, m. Ceram.Soc,73l0)(1990305962 hermal shock resistance and ther 32. Swain, M. v, R-curve behaviour and thermal shock resistance of ceramics. J. Am. Ceram. Soc., 73(3)(1990) ceramic matrix composite. J.Am 621_8 740-3. 33. Pezzotti. G. Tanaka, I.& Ok T, Si,N//SIC 11. Porter J. R.& Chokshi, A. H, Creep performance of whisker composites without sintering aids: 11, fracture haviour. Am. Ceram. s 10)(1990)303945 ture 86, ed, J, A. Pask and A. G. Evans. Pl 4. Ray, A. K, Das, S.K.& Banerjee, S, Fractography of New York, 1986, pp. 919-28 the fatigued and fractured regions in a silicon carbide 12. Tiegs, T.N.& Becher, P. T, Thermal shock behaviour whisker reinforced alumina composite, J. Eur. Ceram of an alumina SiC whisker composite. J. Am. Ceram Soc,705)(1987)C-109l1 35. Hansson, T, Warren, R& Wasen, J, fracture tough512 (2) (3) (4) A. K. Ray, E. R. Fuller, S. Banerjee from the precracked four-point bend speci￾mens were higher and had a value given by K,, = 596 f 0.15 MPa m1’2. The 25 wt% silicon carbide whisker rein￾forced alumina ceramic composite is suscep￾tible to a fatigue crack growth phenomenon which is similar to that observed in the case of metallic materials. But the crack growth exponent is higher (n = 15.5). At low AK fatigue (0.8 to 1 G3 MPa ml”), the whiskers failed by fatigue, whereas during monotonic fracture, they failed by pull-out. 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V., R-curve behaviour and thermal shock resistance of ceramics. J. Am. Ceram. Sot., 73(3) (1990) 521-8. Pezzotti, G., Tanaka, I. & Okamoto, T., Si,N&iC￾lvhisker composites without sintering aids: 11, fracture behaviour. J. Am. Ceram. Sot., 73(10) (1990) 3039-45. Ray, A. K., Das, S. K. & Banerjee, S., Fractography of ihe fatigued and fractured regions in a silicon carbide whisker reinforced alumina composite. J. Eur. Ceram. sot., 15 (1995) 191-9. 35. Hansson, T., Warren, R. & Wasen, J., Fracture tough-