Pressure-less joining of SiCf/SiC composites by Y2O3–Al2O3–SiO2 glass: Microstructure and properties
| Autor: | Le Wang, Haodong Sun, Laifei Cheng, Shangwu Fan, Litong Zhang, Juanli Deng, Biao Ji, Bohan Zheng |
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| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Thermal shock Materials science Process Chemistry and Technology Composite number Mullite 02 engineering and technology 021001 nanoscience & nanotechnology Microstructure 01 natural sciences Cristobalite Thermal expansion Surfaces Coatings and Films Electronic Optical and Magnetic Materials 0103 physical sciences Materials Chemistry Ceramics and Composites Shear strength Brazing Composite material 0210 nano-technology |
| Zdroj: | Ceramics International. 46:27046-27056 |
| ISSN: | 0272-8842 |
| DOI: | 10.1016/j.ceramint.2020.07.181 |
| Popis: | In this study, Y2O3–Al2O3–SiO2 (YAS) glass was prepared from Y2O3, Al2O3, and SiO2 micron powders. Thermal expansion coefficient of as-obtained YAS glass was about 3.9 × 10−6, matching-well with that of SiCf/SiC composites. SiCf/SiC composites were then brazed under pressure-less state by YAS glass and effects of brazing temperature on microstructures and properties of resulting joints were investigated. The results showed that glass powder in brazed seam sintered and precipitated yttrium disilicate, cristobalite, and mullite crystals after heat treatment. With the increase in temperature, joint layer gradually densified and got tightly bonded to SiCf/SiC composite. The optimal brazing parameter was recorded as 1400 °C/30 min and shear strength of the joint was 51.7 MPa. Formation mechanism of glass-ceramic joints was proposed based on combined analysis of microstructure and fracture morphology of joints brazed at different temperatures. Thermal shock resistance testing of joints was also carried out, which depicted decline in shear strength with the increase of thermal shock times. The strength of the joint after three successive thermal shock cycles at 1200 °C was 35.6 MPa, equivalent to 69% of that without thermal shock. |
| Databáze: | OpenAIRE |
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