Thermal expansion and mechanical properties of self-reinforced aluminum titanate ceramics with elongated grains |
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| Affiliation: | 1. Department of Chemistry and Biomolecular Science, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan;2. Japan Fine Ceramics Center, 2-4-1 Mutsuno, Nagoya 456-8587, Japan;1. Institute of Processing and Application of Inorganic Materials, (PAIM), Department of Materials Science and Engineering, Hanseo University, # 360, Seosan-si, Chungnam 356-706, Republic of Korea;2. School of Mechanical Systems Engineering, Kookmin University, 77, Jeongneung-ro, Seongbuk-gu, Seoul 136-702, Republic of Korea;3. Institute of Ceramics, Glass and Construction Materials, Freiberg University, Agricolastrasse 17, 09599 Freiberg, Germany;1. Refractory & Ceramic Materials Division (RCMD), Central Metallurgical R&D Institute (CMRDI), P.O. Box 87 Helwan, 11421 Cairo, Egypt;2. Chemistry Department, Faculty of Science, Helwan University, Helwan, Cairo, Egypt;1. The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China;2. Henan Provincial Key Laboratory of Special Protective Materials, School of Materials Science and Engineering, Luoyang Institute of Science and Technology, Luoyang 471023, China;3. Henan Key Laboratory of High Temperature Functional Ceramics, School of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, China |
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| Abstract: | To fabricate aluminum titanate ceramics that possess both low thermal expansion coefficients and excellent mechanical properties, the co-doping of MgO with Y2O3, La2O3 and Nb2O5 was examined. Doping with MgO lowered the formation reaction temperature of aluminum titanate and prevented the formation of oriented grain regions. Liquid-phase sintering at 1500 °C of the MgO-La2O3-doped ceramic resulted in the formation of a minor amount of elongated grains with lengths of approximately 130 μm. This microstructure resulted in a high resistance against crack propagation during the bend test. Grain pull-out and grain bridging mechanisms as well as crack deflection and branching resulted in the high resistance. A low thermal expansion coefficient of 0.7 × 10?6/deg was observed for this ceramic. The co-doping of MgO Y2O3 led to high bending strength and moderate low thermal expansion coefficient. The co-doping of MgO-Nb2O5 resulted in an extended grain growth by liquid-phase sintering at 1500 °C and poor mechanical properties. |
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| Keywords: | Thermal expansion Fracture Microstructure |
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