Microstructure,Mechanical, and Thermal Properties of (ZrB2 + ZrC)/Zr3[Al(Si)]4C6 Composite |
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| Authors: | Lei Yu Jian Yang Tai Qiu Jingxian Zhang Limei Pan |
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| Affiliation: | 1. College of Materials Science and Engineering, Nanjing Tech University, , Nanjing, 210009 China;2. State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, , Shanghai, 200050 China |
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| Abstract: | The microstructure, mechanical, and thermal properties of in situ hot‐pressed 30 vol% (ZrB2+ZrC)/Zr3Al(Si)]4C6 composite have been investigated and compared with monolithic Zr3Al(Si)]4C6 ceramic. The composite is composed of ZrB2 and ZrC grains embedded in a Zr3Al(Si)]4C6 matrix. The composite shows superior hardness (Vickers hardness of 16.4 GPa), stiffness (Young's modulus of 415 GPa), strength (bending strength of 621 MPa), and toughness (fracture toughness of 7.37 MPa·m1/2) compared with monolithic Zr3Al(Si)]4C6. The composite retains high modulus of 357 GPa at 1430°C (86% of that at ambient temperature) due to clean grain boundaries with no glassy phase. In addition, the composite exhibits higher specific heat capacity and thermal conductivity but slightly lower coefficient of thermal expansion compared with monolithic Zr3Al(Si)]4C6. The calculation of the thermal stress fracture resistance parameter (R) predicts a much improved thermal shock resistance of the composite. Based on these results, (ZrB2+ZrC)/Zr3Al(Si)]4C6 composites show promising potential for high‐temperature and ultra high‐temperature applications. |
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