Enhanced mechanical properties by grain boundary strengthening in ultra-fine grained TZP ceramics


He, Y.J. and Winnubst, A.J.A. and Sagel-Ransijn, C.D. and Burggraaf, A.J. and Verweij, H. (1996) Enhanced mechanical properties by grain boundary strengthening in ultra-fine grained TZP ceramics. Journal of the European Ceramic Society, 16 (6). pp. 601-612. ISSN 0955-2219

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Abstract:The mechanical properties of ceramics with the compositions of 5 mol% YO1.5-TZP (ZY5) and 4 mol% YO1.5-4 mol% CeO2-TZP (ZY4Ce4) were investigated. Nanocrystalline powders of both TZPs were synthesized by a gel precipitation technique. Powder compacts were made by cold isostatic pressing, and were then pressureless sintered or sinter-forged to dense TZP ceramics (density: 96–99%) with grain sizes of 180 nm. Shear deformation during sinter-forging was found to favourably affect densification and microstructure. The mechanical properties of both types of ultrafinegrained TZP ceramics were examined up to 760 °C. The results point towards an improved grain boundary structure and the elimination of residual flaws obtained by the sinter-forging technique. The sinter-forged samples exhibited a higher Vicker hardness compared to that of pressureless sintered specimens. After sinter-forging the fracture energy value was found to be 325 J/m2 and the fracture toughness to be 10 MPa m1/2. A Weibull modulus of 21 was obtained for the sinter-forged samples which was significantly higher than the value of 8 for the pressureless sintered specimens. The enhancement of reliability is obviously connected to a decrease in the average size and concentration of flaws caused by inhomogeneous powder particle packing due to the presence of irregular agglomerates.

Item Type:Article
Copyright:© 1996 Elsevier Science
Science and Technology (TNW)
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Link to this item:http://purl.utwente.nl/publications/12132
Official URL:http://dx.doi.org/10.1016/0955-2219(95)00181-6
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