Hoppressed Si3N4/SiC platelet composites had been investigated with respect to their microstructure and mechanical properties. The results indicate that Vickers hardness, elastic modulus and fracture toughness of the ...Hoppressed Si3N4/SiC platelet composites had been investigated with respect to their microstructure and mechanical properties. The results indicate that Vickers hardness, elastic modulus and fracture toughness of the composites were increased by the addition of SiC platelet until the content up to 20 vol pct. A slight decrease in flexural Strength was measured at room temperature with increasing SiC platelet content. The high temperature flexural strength tests at 1150, 1250, and 1350℃ were conducted. It was found that the flexural strength at elevated temperature was degraded with the rising temperature, and the downward trend of flexural strength for the composite containing 10 vol. pct SiC platelet was less. The results indicate that SiC platelet had a positive influence on the high temperature strength. Effects of SiC platelet reinforcement were presented展开更多
BAS glass-ceramic powders were prepared by sol-gel processing. SiC platelets reinforced BAS glass-ceramic matrix composites with high density and uniform microstructure could be made using hot-pressing method. The rel...BAS glass-ceramic powders were prepared by sol-gel processing. SiC platelets reinforced BAS glass-ceramic matrix composites with high density and uniform microstructure could be made using hot-pressing method. The related processing parameters were studied in this work, including effects of additional seed on transformation from H to M of barium aluminosilicate. DTA method was used to determine exact time to press mixture powders during hot-pressing for the purpose of effective densification. Microstructure and mechanical properties of the composites were investigated by mean of SEM, XRD and TEM techniques as well as three points bending test and single edge notched beam measurement. The results showed that the flexural strength and fracture toughness value of the BAS glass-ceramic matrix composites could be effectively improved by the addition of the SiC platelets. But the relative densities of composites were slightly decreased. The main toughening mechanism is crack deflection, platelets' pull-out and bridging. The increased value of flexural strength is contributed to the load transition effect from matrix to SiC platelets.展开更多
文摘Hoppressed Si3N4/SiC platelet composites had been investigated with respect to their microstructure and mechanical properties. The results indicate that Vickers hardness, elastic modulus and fracture toughness of the composites were increased by the addition of SiC platelet until the content up to 20 vol pct. A slight decrease in flexural Strength was measured at room temperature with increasing SiC platelet content. The high temperature flexural strength tests at 1150, 1250, and 1350℃ were conducted. It was found that the flexural strength at elevated temperature was degraded with the rising temperature, and the downward trend of flexural strength for the composite containing 10 vol. pct SiC platelet was less. The results indicate that SiC platelet had a positive influence on the high temperature strength. Effects of SiC platelet reinforcement were presented
文摘BAS glass-ceramic powders were prepared by sol-gel processing. SiC platelets reinforced BAS glass-ceramic matrix composites with high density and uniform microstructure could be made using hot-pressing method. The related processing parameters were studied in this work, including effects of additional seed on transformation from H to M of barium aluminosilicate. DTA method was used to determine exact time to press mixture powders during hot-pressing for the purpose of effective densification. Microstructure and mechanical properties of the composites were investigated by mean of SEM, XRD and TEM techniques as well as three points bending test and single edge notched beam measurement. The results showed that the flexural strength and fracture toughness value of the BAS glass-ceramic matrix composites could be effectively improved by the addition of the SiC platelets. But the relative densities of composites were slightly decreased. The main toughening mechanism is crack deflection, platelets' pull-out and bridging. The increased value of flexural strength is contributed to the load transition effect from matrix to SiC platelets.
