Enhancing thermal stability of oxide ceramic matrix composites via matrix doping |
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| Affiliation: | 1. Advanced Ceramics, Universität Bremen, Bremen 28359, Germany;2. MAPEX - Center for Materials and Processes, Universität Bremen, Bremen 28359, Germany;1. Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan;2. Graduate School of Advanced Technology, National Taiwan University, Taipei 10617, Taiwan;1. Institut für Werkstoffe der Elektrotechnik II, RWTH Aachen, 52074 Aachen, Germany;2. Research Center Jülich, PGI 7, 52425 Jülich, Germany;1. School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China;2. State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, China;3. ISCR (Institut Des Sciences Chimiques de Rennes) ? UMR 6226, CNRS, Univ Rennes, 35000 Rennes, France;1. Shi-changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China;2. School of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China;3. CAS Key Laboratory of Nuclear Materials and Safety Assessment, IMR(NMSA), Shenyang 110016, China |
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| Abstract: | To overcome the main limitation of oxide ceramic matrix composites (Ox-CMCs) regarding thermal degradation, the use of matrix doping is analyzed. Minicomposites containing Nextel 610 fibers and alumina matrices with and without MgO doping were produced. The thermal stability of the minicomposites was evaluated considering their microstructure and mechanical behavior before and after thermal exposures to 1300 °C and 1400 °C for 2 h. Before heat treatment, both composite types showed very similar microstructure and tensile strength. After heat treatment, densification, grain growth and strength loss are observed. Furthermore, the MgO dopant from the matrix diffuses into the fibers. As a result, abnormal fiber grain growth is partially suppressed and MgO-doped composites show smaller fiber grains than non-doped composites. This more refined microstructure leads to higher strength retention after the heat treatments. In summary, doping the matrix can increase the overall thermal stability without impairing the room-temperature properties of Ox-CMCs. |
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| Keywords: | Ceramic matrix composites Nextel 610 Alumina Magnesia Grain growth |
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