1556 J. Pascual et aL /Joumal of the European Ceramic Sociery 28(2008)1551-1556 laminated composites loaded in flexural geometry. Comp. Sci. Technol., 31 Oel, H J. and Frechette, V. D, Stress distribution in multiphase 2005,65,1501-1506 tems. I: Composites with planar interfaces. J. Am. Ceram. Soc., 1967 21. Bermejo, R, Pascual Herrero, J, Lube, T and Danzer, R, Optimal strength 542-549 nd toughness of Al2O3-ZrO2-laminates designed with external or intemal 32. Pascual Herrero, J, Influence of residual stresses on strength and toughness compressive layers. J. Eur Ceram. Soc., 2008, 28, 1575-1583 of an alumina/alumina-zirconia laminate Dissertation. montanuniversitat 22. Bermejo, R, Torres, Y, Sanchez-Herencia, A J, Baudin, C, Anglada, M. and Llanes, L, Residual stresses, strength and toughness of laminates with 33. Pascual Herrero, J, Chalvet, F, Lube, T. and de Portu, G, Strength different layer thickness ratios. Acta Mater, 2006, 54(18),4745-4757 distributions ramic laminates. Mater. Sci. Forum. 2005. 492/493 23. Cutler, R. A, Bright, J. D, Virkar, A. V. and Shetty, D. K, Strength 581-586. improvement in transformation-toughened alumina by selective phase trans- 34. Cai, P. Z, Green, D J and Messing, G L, Constrained densification of formation. J Am. Ceram. Soc.. 1987, 70(10), 714-718. alumina/zirconia hybrid laminates. Il: Viscoelastic stress computation. J. 24. Lakshminarayanan, R, Shetty, D. K. and Cutler, R. A Toughening of lay Am. Ceran.SoC.,1997,80(8),1940-1948. composites with residual surface compression. J Am Ceram. 35. Chiang. Y-M, Birnie, D I and Kingery, D. w, Physical Ceramics. John Soe.1996,79(1),79-87 Wiley Sons, Inc, New York, 1997, Pp 522. 25. Lugovy, M, Slyunyayev, V, Orlovskaya, N, Blugan, G, Kubler, J and 36 Danzer, R, Lube, T and Supancic, P, Monte-Carlo simulations of strength ewis, M. H, Apparent fracture toughness of Si3 Na-based laminates with distributions of brittle materials-type of distribution, specimen- and sample residual compressive or tensile stress in surface layers. Acta Mate, 2005 size. Zf. Metallica.,2001,927),773-783 53,289-296 37. Danzer,R. Supancic, P, Pascual Herrero, J and Lube, T, Fracture statistics 26. Blattner, A.J., Lakshminarayanan, R and Shetty, D. K, Toughening of of ceramics-Weibull statistics and deviations from Weibull statistics. Eng layered ceramic composites with residual surface compression: effects of Fract. Mech., 2007, 74(18), 2919-2932 layer thickness. Eng. Fract. Mech., 2001, 68, 1-7. 38. Lu. C. Danzer. R. and Fischer. F.D. Fracture statistics of brittle materials. 27. Sglavo, V M. Paternoster, M. and Bertoldi, M. Tailored residual stresses Weibull or normal distribution. Phys. Rev. E, 2002, 65(6)(Article Number in high reliability alumina-mullite ceramic laminates. J. Am. Ceram. Soc. 067102) 2005,88(10,2826-2832. 39. Lu. C. Danzer. R. and Fischer. F. D. Influence of threshold stress 28. Lube. T. Pascual Herrero, J. Chalvet. F. and de portu. G. Effective frac- the estimation of the Weibull Statistics. J. Am. Ceram. Soc., 2002. 85(6 ture toughness in Al2O3-Al2O3/rO2 laminates. J. Eur: Ceram. Soc., 2007, 1640-1642. 7(2/3),1449-1453 40. Fett, T. Ernst, E, Munz, D, Badenheim, D. and Oberacker, R, Weibull 29. Tarlazzi, A, Roncar E, Pinasco, P. Guicciardi, S, Melandri. C. and de analysis of ceramics under high stress gradients. J. Eur. Ceram Soc., 2003 Portu, G. Tribological behaviour of Al2O3IZro2-ZrO2 laminated compos 3.2031-2037. s.Wear,2000,244(1/2),2940 41. Danzer, R, Reisner, G. and Schubert, H. Der EinfluB von Gradienten in der 30. Pascual Herrero, J. Chalvet, F, Lube, T. and De Portu. G, R-curves in Defektdichte und Festigkeit auf die Bruchstatistik von sproden Werkstoffen. Al2O3-Al2O3/Zro2 laminates key. Eng Mater, 2005, 290, 214-221 Z. f Metalled,1992,83.508-5171556 J. Pascual et al. / Journal of the European Ceramic Society 28 (2008) 1551–1556 laminated composites loaded in flexural geometry. Comp. Sci. Technol., 2005, 65, 1501–1506. 21. Bermejo, R., Pascual Herrero, J., Lube, T. and Danzer, R., Optimal strength and toughness of Al2O3–ZrO2-laminates designed with external or internal compressive layers. J. Eur. Ceram. Soc., 2008, 28, 1575–1583. 22. Bermejo, R., Torres, Y., Sanchez-Herencia, A. J., Baudin, C., Anglada, M. and Llanes, L., Residual stresses, strength and toughness of laminates with different layer thickness ratios. Acta Mater., 2006, 54(18), 4745–4757. 23. Cutler, R. A., Bright, J. D., Virkar, A. V. and Shetty, D. K., Strength improvement in transformation-toughened alumina by selective phase trans￾formation. J. Am. Ceram. Soc., 1987, 70(10), 714–718. 24. Lakshminarayanan, R., Shetty, D. K. and Cutler, R. A., Toughening of lay￾ered ceramic composites with residual surface compression. J. Am. Ceram. Soc., 1996, 79(1), 79–87. 25. Lugovy, M., Slyunyayev, V., Orlovskaya, N., Blugan, G., Kubler, J. and ¨ Lewis, M. H., Apparent fracture toughness of Si3N4-based laminates with residual compressive or tensile stress in surface layers. Acta Mater., 2005, 53, 289–296. 26. Blattner, A. J., Lakshminarayanan, R. and Shetty, D. K., Toughening of layered ceramic composites with residual surface compression: effects of layer thickness. Eng. Fract. Mech., 2001, 68, 1–7. 27. Sglavo, V. M., Paternoster, M. and Bertoldi, M., Tailored residual stresses in high reliability alumina–mullite ceramic laminates. J. Am. Ceram. Soc., 2005, 88(10), 2826–2832. 28. Lube, T., Pascual Herrero, J., Chalvet, F. and de Portu, G., Effective frac￾ture toughness in Al2O3–Al2O3/ZrO2 laminates. J. Eur. Ceram. Soc., 2007, 27(2/3), 1449–1453. 29. Tarlazzi, A., Roncari, E., Pinasco, P., Guicciardi, S., Melandri, C. and de Portu, G., Tribological behaviour of Al2O3/ZrO2–ZrO2 laminated compos￾ites. Wear, 2000, 244(1/2), 29–40. 30. Pascual Herrero, J., Chalvet, F., Lube, T. and De Portu, G., R-curves in Al2O3–Al2O3/ZrO2 laminates key. Eng. Mater., 2005, 290, 214–221. 31. Oel, H. J. and Frechette, V. D., Stress distribution in multiphase sys￾tems. I: Composites with planar interfaces. J. Am. Ceram. Soc., 1967, 50, 542–549. 32. Pascual Herrero, J., Influence of residual stresses on strength and toughness of an alumina/alumina–zirconia laminate. Dissertation, Montanuniversitat, ¨ Leoben, 2007. 33. Pascual Herrero, J., Chalvet, F., Lube, T. and de Portu, G., Strength distributions in ceramic laminates. Mater. Sci. Forum, 2005, 492/493, 581–586. 34. Cai, P. Z., Green, D. J. and Messing, G. L., Constrained densification of alumina/zirconia hybrid laminates. II: Viscoelastic stress computation. J. Am. Ceram. Soc., 1997, 80(8), 1940–1948. 35. Chiang, Y.-M., Birnie, D. I. and Kingery, D. W., Physical Ceramics. John Wiley & Sons, Inc., New York, 1997, pp. 522. 36. Danzer, R., Lube, T. and Supancic, P., Monte-Carlo simulations of strength distributions of brittle materials—type of distribution, specimen- and sample size. Z. f. Metallkd., 2001, 92(7), 773–783. 37. Danzer, R., Supancic, P., Pascual Herrero, J. and Lube, T., Fracture statistics of ceramics—Weibull statistics and deviations from Weibull statistics. Eng. Fract. Mech., 2007, 74(18), 2919–2932. 38. Lu, C., Danzer, R. and Fischer, F. D., Fracture statistics of brittle materials: Weibull or normal distribution. Phys. Rev. E, 2002, 65(6) (Article Number 067102). 39. Lu, C., Danzer, R. and Fischer, F. D., Influence of threshold stress on the estimation of the Weibull Statistics. J. Am. Ceram. Soc., 2002, 85(6), 1640–1642. 40. Fett, T., Ernst, E., Munz, D., Badenheim, D. and Oberacker, R., Weibull analysis of ceramics under high stress gradients. J. Eur. Ceram. Soc., 2003, 23, 2031–2037. 41. Danzer, R., Reisner, G. and Schubert, H., Der Einfluß von Gradienten in der Defektdichte und Festigkeit auf die Bruchstatistik von sproden Werkstoffen. ¨ Z. f. Metallkd., 1992, 83, 508–517