Fabrication of Ceramic Fiber-reinforced Alumina Composites Using Reactive Infiltration

在Al_2O_3粉末、Al_2O_3纤维、ZrO_2纤维、SiC晶须、SiC纤维和Si-Ti-C-O纤维包埋的Al_2O_3和Tohdo预制体中渗透熔融Al，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：(1)采用Pyrex玻璃，在1050℃的温度下浸润5mm厚度的预制体3h。(2)压坯的孔隙率由50vol%降至4-10vol%。(3)随着SiC晶须含量的增加，复合材料的抗弯强度从500 mpa下降到309MPa，而断裂韧性则从3.8 mpam ^<1/2>增加到4.5MPam^<1/2>。(4) SiC纤维添加量为5wt%时，复合材料的抗弯强度为403MPa，断裂韧性为3.1MPam^<1/2>。(5) Al_2O_3纤维复合材料的抗弯强度为306MPa。(1)在适当温度下，Tohdo/Al_2O_3颗粒的入渗速率最大。所得Al_2O_3/Al/Si复合材料的抗弯强度和断裂韧性分别为240MPa和4.3MPam^<1/2>。(2) Tohdo与ZrO_2纤维的复合材料为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降至110MPa，而断裂韧性基本保持不变。(3)含Tohdo的Si-Ti-C-O纤维复合材料的抗弯强度随着纤维含量的增加从240 mpa降低到70MPa，而断裂韧性从3.3 mpa增加到6.6 mpa ^<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>.