Mechanical and thermal properties of δ-RE4Hf3O12 (RE = Yb,Lu) |
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| Authors: | Wanpeng Hu Guangheng Zhang Yiming Lei Luchao Sun Jie Zhang Jingyang Wang |
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| Affiliation: | 1. Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China
School of Materials Science and Engineering, University of Science and Technology of China, Shenyang, China;2. Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China |
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| Abstract: | Rare-earth (RE) hafnates are promising thermal and environmental barrier coating (TEBC) materials for SiCf/SiC ceramic matrix composites. In this study, pure-phase and dense δ-RE4Hf3O12 (RE = Yb, Lu) bulk ceramics have been fabricated via a hot-pressing method. The crystal structure, microstructure, mechanical, and thermal properties of δ-RE4Hf3O12 were systematically investigated in order to probe their potential application as TEBCs. The high-temperature elastic moduli of δ-Yb4Hf3O12 and δ-Lu4Hf3O12 are measured to be 185 and 188 GPa at 1673 K, respectively, which are over 85% values of room temperature. The coefficients of thermal expansion are 7.64 × 10−6 and 7.46 × 10−6 K−1 for δ-Yb4Hf3O12 and δ-Lu4Hf3O12, respectively. The relatively low coefficient of thermal expansion and thermal conductivity as well as their excellent high-temperature stability endow these hafnates as potential TEBC candidates. |
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| Keywords: | mechanical property rare-earth hafnate thermal and environmental barrier coating thermal property |
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