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Effects of Growth Rate on Microstructure and Properties of Directionally Solidified Eutectic Ceramic Al2O3/MgAl2O4/ZrO2
Z. Chu1,2, S. Wang1,2, J. Liu1,2, J. Wang1,2
1 School of Material Science and Engineering, Shandong University of Technology, Zibo 255049, China
2 National Engineering Research Center of Industrial Ceramics of China, 12 Zhangzhou Road, Zibo 255049, China
received September 18, 2017, received in revised form November 23, 2017, accepted Januar 9, 2018
Vol. 9, No. 1, Pages 61-68 DOI: 10.4416/JCST2017-00076
Abstract
Directionally solidified Al2O3/MgAl2O4/ZrO2 ternary eutectic ceramic was prepared by means of induction heating zone melting (IHZM), and the effects of the growth rate on the microstructure and properties of the solidified ceramic were investigated. X-ray diffraction (XRD) patterns showed that the eutectic rod contained Al2O3, MgAl2O4 and ZrO2 phases. The results of scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) demonstrated that Al2O3/MgAl2O4 constituted the matrix of the eutectic ceramic while rod-like ZrO2 was uniformly embedded in the matrix. The specimen morphology is transformed from an irregular pattern to a regular bar-shaped pattern with the increase in the growth rate. The measured and calculated value of λ2ν (λ, the phase spacing; ν, the solidification rate) was approximately equal to 2.98, which fitted well with the formula: λ2ν = constant. With the increase in the growth rate, the hardness of the material decreases, the fracture toughness first increases and then decreases. The maximum hardness of the solidified eutectic ceramic rate reached 11.68 GPa when the solidification rate was 1 mm/h, this hardness was about 1.6 times that of the pre-sintered sample. Its maximum fracture toughness at room temperature was 7.21 MPa·m1/2 when the rate was 3 mm/h, which was about two times that of the pre-sintered sample.
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Keywords
Al2O3/MgAl2O4/ZrO2, eutectic oxide ceramic, growth rate, induction zone melting, microstructure, fracture toughness
References
1 Otuska, D., Waku, Y., Kitagawa, K., Arai, N.: Effect of hot corrosive environment on ceramics, Energy., 30, 523 – 533, (2005).
2 Stubican, V.S., Bradt, R.C.: Eutectic solidification in ceramic systems, Ann. Rev. Mater. Sci., 11, [1], 267 – 297, (1981).
3 Viechnicki, D., Schmid, F.: Investigation of the eutectic point in the system Al2O3-Y3Al5O12, Mater. Res. Bull., 4, 129 – 135, (1969).
4 Waku, Y., Nakagawa, N., Wakamoto, T.: A ductile ceramic eutectic composite with high strength at 1873 K, Nature., 389, 49, (1997).
5 Waku, Y.: A new ceramic eutectic composite with high strength at 1873 K, Adv. Mater., 10, 615 – 617, (1998).
6 Pastor, J.Y., LLorca, J., Salazar, A.: Mechanical properties of melt-grown Alumina-Yttrium aluminum garnet eutectics up to 1900 K, J. Am. Ceram. Soc., 88, 1488 – 1498, (2005).
7 Song, T.T.: Microstructure and mechanical properties of Al2O3/ZrO2 directionally solidified eutectic ceramic prepared by laser 3D printing, J. Mater. Sci. Technol., 32, 320 – 325, (2016).
8 Song, K., Zhang, J., Lin, X.: Microstructure and mechanical properties of Al2O3/Y3Al5O12/ZrO2 hypereutectic directionally solidified ceramic prepared by laser floating zone, J. Eur. Ceram. Soc., 34, 3051 – 3059, (2014).
9 Ohashi, Y., Yasui, N., Suzuki, T.: Orientation relationships of unidirectionally aligned GdAlO3/Al2O3 eutectic fibers, J. Eur. Ceram. Soc., 34, 3849 – 3857, (2014).
10 Mesa, M.C., Oliete, P.B., Orera, V.M.: Microstructure and mechanical properties of Al2O3/ Er3Al5O12 eutectic rods grown by the laser-heated floating zone method, J. Eur. Ceram. Soc., 31, 1241 – 1250, (2011).
11 Zhai, S., Liu, J.C., Wang, J.: Microstructure of the directionally solidified ternary eutectic ceramic Al2O3/MgAl2O4/ZrO2, Ceram. Int., 42, 8079 – 8084, (2016).
12 McKittricka, J., Kalonjib, G.: Non-stoichiometry and defect structures in rapidly solidified MgO-Al2O3-ZrO2 ternary eutectics, Mat. Sci. Eng., A231, 90 – 97, (1997).
13 Jackson, K.A.: Constitutional supercooling surface roughening, J. Cryst. Growth, 264, 519 – 529, (2004).
14 Su, H.J., Zhang, J., Liu, L., Fu, F.H.: Processing and microstructure of Al2O3/YAG eutectic ceramic by laser rapid remelting, J. B. Univ. Aeronaut. Astronaut., 33, [7], 846 – 850, (2007).
15 Pastor, J.Y., Llorca, J., Poza, P.: Mechanical properties of melt-grown Al2O3–ZrO2 (Y2O3) eutectics with different microstructure, J. Eur. Ceram. Soc., 25, 1215 – 1223, (2005).
16 Deng, Y.F., Zhang, J., Su, H.J.: Microstructure and fracture toughness of Al2O3/Er3Al5O12 eutectic ceramic prepared by laser zone remelting, J. Inorg. Mater., 26, 841 – 846, (2011).
17 Ge, Q.L., Zhou, Y., Lei, Y.Q.: Study on microstructure and properties of ZrO2-2 mol% Y2O3 ceramics, in chinese, J. Chin. Ceram. Soc., 1, 47 – 53, (1990).
18 Yashima, M., Kakihana, M., Yoshimura, M.: Metastable-stable phase diagrams in the zirconia-containing systems utilized in solid-oxide fuel cell application, Solid State Ionics, 86 – 88, [96], 1131 – 1149, (1996).
19 Su, H., Zhang, J., Cui, C.: Growth characteristic of Al2O3/Y3Al5O12 (YAG) eutectic ceramic in situ composites by laser rapid solidification, J. Alloy. Compd., 456, 518 – 523, (2008).
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