Fabrication of Ceramic Fiber-reinforced Alumina Composites Using Reactive Infiltration

通过在Al_2O_3和Tohdo预制体中渗入Al_2O_3粉末、Al_2O_3纤维、ZrO_2纤维、碳化硅晶须、碳化硅纤维和Si-Ti-C-O纤维，制备了陶瓷纤维增强Al_2O_3/金属复合材料。得到了以下结果。(Al_2O_3预制件)(1)用高温玻璃在1050ﾟC下浸渗5 mm厚的预制件3h。(2)压坯的气孔率由50vol%降至4-10vol%。(3)随着碳化硅晶须含量的增加，复合材料的抗弯强度从500 Mpa降低到309 Mpa，断裂韧性从3.8提高到4.5MPam；(4)当碳化硅纤维含量为5wt%时，复合材料的弯曲强度和断裂韧性分别为403 Mpa和3.1MPam；(5)含Al_2O_3纤维的复合材料的弯曲强度为306 Mpa。(1)Tohdo/Al_2O_3颗粒的渗透速率在合适的温度下达到最大值。制得的Al_2O_3/Al/Si复合材料的弯曲强度和断裂韧性分别为240 Mpa和4.3MPam 1/2。(2)由Tohdo/ZrO_2纤维组成的复合材料为Al_2O_3/Al/Si/ZrSi_2。随着纤维含量的增加，复合材料的抗弯强度从360 Mpa下降到110 Mpa，但断裂韧性基本不变。(3)随着纤维含量的增加，含Tohdo的Si-Ti-C-O纤维复合材料的弯曲强度从240 Mpa下降到70 Mpa，断裂韧性从3.3增加到6.6MPam^&lt；1/2；

Ceramic fiber-reinforced Al_2O_3/metal composites were fabricated by infiltrating molten Al into the Al_2O_3 and Tohdo preforms embedded with Al_2O_3 powder, Al_2O_3 fiber, ZrO_2 fiber, SiC whisker, SiC fiber, and Si-Ti-C-O fibers. The following results were obtained. (Al_2O_3 preform) (1) The preform of 5mm in thickness could be infiltrated at 1050ﾟC for 3h using Pyrex glass. (2) The porosity of the compact decreased from 50vol% to 4-10vol%. (3) The bending strength of the composites decreased from 500 to 309MPa with increasing SiC whisker content, but the fracture toughness increased from 3.8 to 4.5MPam^<1/2> with it. (4) The bending strength and the fracture toughness of the composite with 5wt% of SiC fiber were 403MPa and 3.1MPam^<1/2>, respectively. (5) The bending strength of the composite with Al_2O_3 fiber were 306MPa. (Tohdo Preform) (1) The infiltration rate into Tohdo/Al_2O_3 particles took a maximum value at an appropriate temperature. The bending strength and the fracture toughness of the resulting Al_2O_3/Al/Si composite were 240MPa and 4.3MPam^<1/2>, respectively. (2) The composite from the Tohdo with ZrO_2 fiber was Al_2O_3/Al/Si/ZrSi_2. The bending strength of the composites decreased from 360 to 110MPa with increasing fiber content, but the fracture toughness was almost constant. (3) The bending strength of the composites from Si-Ti-C-O fiber containing Tohdo decreased from 240 to 70MPa with increasing fiber content, but the fracture toughness increased from 3.3 to 6.6MPam^<1/2>.