Articles
All articles | Recent articles
Effect of In Situ-Formed Cerium Hexaaluminate Precipitates on Properties of Alumina -24 Vol% Zirconia (1.4Y) Composites
F. Kern
University of Stuttgart, IFKB, Allmandring 7B, D-70569 Stuttgart, Germany
received May 14, 2013, received in revised form June 18, 2013, accepted August 5, 2013
Vol. 4, No. 4, Pages 177-186 DOI: 10.4416/JCST2013-00014
Abstract
In situ-platelet-reinforced zirconia-toughened alumina ceramics have become established materials, successfully replacing alumina and zirconia in hip implants. While the beneficial effect of the in situ toughening seems undoubted, this toughening mechanism is still not fully understood.
A nanocomposite ZTA containing 24 vol% partially stabilized zirconia (1.4Y-TZP) was reinforced with 10 vol% cerium hexaaluminate (CA6) by reacting in situ-reduced ceria with alumina during hot pressing. The mechanical properties, evolution of microstructure and phase composition of the CA6-containing ZTA were compared with the properties of the non-reinforced reference.
The unreinforced ZTA24 shows a microstructure with modular matrix grains and ultrafine zirconia dispersion. High strength of 1150 MPa but moderate toughness of 5 MPa·√m and low transformability of the zirconia dispersion was observed. The CA6-reinforced material shows higher toughness and transformability combined with a trade-off in hardness and strength. The CA6 precipitates are rod-shaped, well dispersed and oriented normal to the pressing direction. The formation of CA6 especially at sintering temperatures exceeding 1500 °C is associated with microstructural coarsening and a broadening of grain size distribution of matrix and dispersion, making the zirconia more transformable. Crack deflection at matrix-precipitate grain boundaries was not observed.
Download Full Article (PDF)
Keywords
Alumina, zirconia, platelets, mechanical properties, microstructure
References
1 Wang, J., Stevens. R.: Zirconia-toughened alumina (ZTA) ceramics, J. Mater. Sci., 24, 3421 – 3440, (1989).
2 Becher, P.F.: Slow crack growth behavior in transformation-toughened Al2O3-ZrO2(Y2O3) ceramics, J. Am. Ceram. Soc., 66, [7], 485 – 488, (1983).
3 Claussen, N.: Fracture toughness of Al2O3 with an unstabilized ZrO2 dispersed phase, J. Am. Ceram. Soc., 59, [1 – 2], 49 – 51, (1976).
4 Gregori, G., Burger, W., Sergo, V.: Piezo-spectroscopic analysis of the residual stresses in zirconia-toughened alumina ceramics: the influence of the Tetragonal-to-monoclinic transformation, Mater. Sci. Eng. A, 271, 401 – 406, (1999).
5 Garcia D.E., Rödel, J., Claussen, N.: Subcritical crack growth and R-curve behavior in Al2O3-Toughened Y-TZP, in Science and Technology of Zirconia V. Technomic Publishing, Lancaster, USA, 1993.
6 Cutler, R.A., Mayhew, R.J., Prettyman, K.M., Virkar, A.V.: High-toughness Ce-TZP/Al2O3 ceramics with improved hardness and strength, J. Am. Ceram. Soc., 74, [1], 179 – 86, (1991).
7 Burger, W., Richter, H.G.: High strength and toughness alumina matrix composites by transformation toughening and in situ platelet reinforcement (ZPTA) – the new generation of bioceramics, Key Eng. Mat., 192 – 195, 545 – 548, (2001).
8 Chevalier, J., Grandjean, S., Kuntz, M., Pezzotti, G.: On the kinetics and impact of tetragonal to monoclinic transformation in an alumina/zirconia composite for arthroplasty applications, Biomaterials, 30, [29], 5279 – 5282, (2009).
9 Wu, Y., Zhang, Y., Huang, X., Guo, J.: In-situ growth of needle-like LaAl11O18 for reinforcement of alumina composites, Ceram. Int., 27, 903 – 906, (2001).
10 Jin, X., Gao, L.: Effects of powder preparation method on the microstructure and mechanical performance of ZTA/LaAl11O18 composites, J. Eur. Ceram. Soc., 24, 653 – 659, (2004).
11 Huang, S., Li, L., Vleugels, J., Wang, P., Van der Biest, O.: Thermodynamic prediction of the nonstoichiometric phase Zr1-zCezO2-x in the ZrO2-CeO1.5-CeO2 system, J. Eur. Ceram. Soc., 23, 99 – 106, (2003).
12 Tsukuma, K.: Conversion from β-Ce2O3 · 11 Al2O3 to α-Al2O3 in tetragonal ZrO2 matrix, J. Am. Ceram. Soc., 83, [12], 3219 – 21, (2000).
13 Akin, I., Yilmaz, E., Sahin, F., Yucel, O., Goller, G.: Effect of CeO2 addition on densification and microstructure of Al2O3-YSZ composites, Ceram. Int., 37, 3273 – 3280, (2011).
14 Kern, F.: Structure-property relations in alumina-zirconia nanocomposites reinforced with in situ formed cerium hexaaluminate precipitates, Scripta Mater., 67, [12], 1007 – 1010, 2012.
15 Sommer, F., Landfried, R., Kern, F., Gadow, R.: Mechanical properties of zirconia toughened alumina with 10 – 24 vol% 1.5 mol% Y-TZP reinforcement, J. Eur. Ceram. Soc., 32, [15], 3905 – 3910, (2012).
16 Chantikul, P., Anstis, G.R., Lawn, B.R., Marshall, D.B.: A critical evaluation of indentation techniques for measuring fracture toughness: II, strength method, J. Am. Ceram. Soc., 64, [9], 539 – 543, (1981).
17 Braun, L.M., Benninson, S.J., Lawn, B.R.: Objective evaluation of short-crack toughness curves using indentation flaws: case study on alumina-based ceramics, J. Am. Ceram. Soc., 75, [11], 3049 – 57, (1992).
18 Dransmann, G., Steinbrech, R., Pajares, A., Guiberteau, F., Dominguez-Rodriguez, A., Heuer, A.: Indentation studies on Y2O3,-stabilized ZrO2: II, Toughness determination from stable growth of indentation-induced cracks, J. Am. Ceram. Soc., 77, [5], 1194 – 201, (1994).
19 Benzaid, R., Chevalier, J., Saadaoui, M., Fantozzi, G., Nawa, M., Diaz, L.A., Torrecillas, R.: Fracture toughness, strength and slow crack growth in a ceria stabilized zirconia-alumina nanocomposite for medical applications, Biomaterials, 29, 3636 – 3641, (2008).
20 Kern, F.: Gadolinia-Neodymia-Co-stabilized zirconia materials with high toughness and strength, J. Ceram. Sci. Techn., 3, [3], 119 – 130, (2012).
21 Toraya, H., Yoshimura, M., Somiya, S.: Calibration curve for quantitative analysis of the monoclinic-tetragonal ZrO2 system by X-ray diffraction, J. Am. Ceram. Soc., 67, [6], C119 – 121, (1984).
22 Kosmac, T., Wagner, R., Claussen, N.: X-ray determination of transformation depths in ceramics containing tetragonal ZrO2, J. Am. Ceram. Soc., 64, [4], C72 – 73, (1981).
23 McMeeking, R., Evans, A.G.: Mechanics of transformation toughening in brittle materials, J. Am. Ceram. Soc., 65, [5], 242 – 246, (1982).
24 Mendelson, M.I.: Average grain size in polycrystalline ceramics, J. Am. Ceram. Soc., 52, [8], 443 – 446, (1969).
25 Lube, T., Fett, T: A threshold stress intensity factor at the onset of stable crack extension of knoop indentation cracks, Eng. Fract. Mech., 71, 2263 – 2269, (2004).
26 Gutknecht, D., Chevalier, J., Garnier, V., Fantozzi, G.: Key role of processing to avoid low temperature ageing in alumina zirconia composites for orthopaedic application, J. Eur. Ceram. Soc., 27, 1547 – 1552, (2007).
27 Heuer, A.H., Claussen, N., Kriven, W.M., Rühle, M.: Stability of tetragonal ZrO2 particles in ceramic matrices, J. Am. Ceram. Soc., 65, [12], 642 – 650, (1982).
28 He, M.Y., Hutchinson, J.W.: Kinking of a crack out of an interface, J. Appl. Mech., 56, 270 – 278, (1989).
29 Lakiza, S.M., Lopato, L.M.: Phase diagram of the Al2O3-ZrO2-La2O3 system, J. Eur. Ceram. Soc., 25, 1373 – 1380, (2005).
30 Wang, C., Zinkevich, M., Aldinger, F.: Phase diagrams and thermodynamics of rare-earth-doped zirconia ceramics, Pure Appl. Chem., 79, (10), 1731 – 1753, (2007).
Copyright
Göller Verlag GmbH