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Low-shrinkage alumina−mullite composites were fabricated by reaction bonding using α-Al 2 O 3 , Al, β-SiC and 3Y-ZrO 2 as the starting powders. The effects of ZrO 2 addition and sintering temperature on densification behaviour and mechanical properties were investigated. It is shown that the addition of ZrO 2 can effectively inhibit grain growth and significantly accelerate densification. At a sintering temperature of 1580°C, 15 vol.% ZrO 2 -containing alumina−mullite composites were sintered to 97.4% of the theoretical density. Due to a relatively homogeneous microstructure without large abnormal grains, such composites exhibited a highly intergranular fracture mode. As a result, a high strength up to 575 MPa was obtained. |
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