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Al2O3- Si- Al composite specimens with the size of25 mm × 25 mm × 125 mm were prepared using fused alumina( as aggregates and fines),ultra-fine α-Al2O3,Si and Al powders as starting materials,liquid phenol formaldehyde resin as the binder,pressing and heating at 800- 1 500 ℃ for 3 h under carbon embedded condition. Evolution of phase composition and microstructure of Al2O3- Si- Al composite during heating from 800 to1 500 ℃ under carbon embedded condition were studied. The results show that:( 1) Al4C3,AlN and SiC are initially formed at 800- 900 ℃ due to reactions of Al and Si with C or CO and N2;( 2) at 1 000-1 300 ℃,the amounts of Al4C3,AlN and SiC increase with temperature rising and their crystals grow;( 3) at 1 400-1 500 ℃,Al4C3 and AlN disappear,and minor SiA lO N crystals are observed; the nonoxide crystals develop well and they are interlaced in the corundum skeleton structure, which creates strengthening and toughening effects.
Al2O3-Si-Al composite specimens with the size of 25 mm × 25 mm × 125 mm were prepared using fused alumina (as aggregates and fines), ultra-fine α-Al2O3, Si and Al powders as starting materials, liquid phenol formaldehyde resin as The binder, pressing and heating at 800-1 500 ° C for 3 h under carbon embedded condition. Evolution of phase composition and microstructure of Al2O3- Si- Al composite during heating from 800 to1 500 ° C under carbon embedded condition were studied. The results show that: (1) Al4C3, AlN and SiC are initially formed at 800-900 ° C due to reactions of Al and Si with C or CO and N2; (2) at 1000-1 300 ° C, the amounts of Al4C3, AlN and (3) at 1 400-1 500 ° C, Al4C3 and AlN disappear, and minor SiAlO crystals are observed; the nonoxide crystals develop well and they are interlaced in the corundum skeleton structure, which creates strengthening and toughening effects.