连续纤维增韧碳化硅陶瓷基复合材料研究

RESEARCH ON CONTINUOUS FIBER REINFORCED SILICON CARBIDE COMPOSITES

采用化学气相浸渗法制造了连续碳纤维和碳化硅纤维增韧碳化硅陶瓷基复合材料 ,并对复合材料的显微结构和力学性能进行了研究 .C/SiC和SiC/SiC复合材料的密度分别为 2 .1g/cm3和 2 .5 g/cm3,在断裂过程中表现出明显的非线形和非灾难性的断裂行为和规律 .C/SiC和SiC/SiC弯曲强度分别为 45 0MPa和 860MPa ,从室温至 160 0℃强度不发生降低 ;断裂韧性为 2 0MPa·m1 / 2 和 41.5MPa·m1 / 2 ,断裂功为 10kJ·m- 2 和 2 8.1kJ·m- 2 ,冲击韧性为 62 .0kJ·m- 2 和 3 6.0kJ·m- 2 .C/SiC和SiC/SiC复合材料具有优异的抗热震性能 ,经 13 0 0℃ 3 0 0℃ ,5 0次热震后 ,强度保持率高达 96.4% ,热震不是材料性能损伤的控制因素 .而SiC/SiC复合材料优异的抗氧化性能 ,对温度梯度不敏感 .

Silicon carbide textile composites reinforced with continuous carbon and silicon carbide fiber were fabricated by chemical vapor infiltration. The densities of C/SiC and SiC/SiC composites after 30 h infiltration are 2.1 g·cm -3 and 2.5 g·cm -3 respectively . The values of flexural strength of C/SiC and SiC/SiC composites are 450 MPa and 860 MPa respectively, which are not reduced as temperature increased from room temperature to 1 600 ℃. Accordingly, the values of fracture toughness are 20 MPa·m 1/2 and 41.5 MPa·m 1/2 , fracture work, 10 kJ·m -2 and 28.1 kJ·m -2 , dynamic impact fracture toughness, 62.0 kJ·m -2 and 36.0 kJ·m -2 , respectively. After thermal shock tests between 300 ℃ and 1 300 ℃ for 50 times, the flexural strength is retained by 96.4%. It indicate that thermal shock was not the controlling factor for the failure of C/SiC and SiC/SiC materials. Compared with C/SiC, SiC/SiC exhibits superior oxidation resistance. Especially, both C/SiC and SiC/SiC thruster chambers successfully passes the test in rocket engine.