加压烧结工艺对碳纤维增强TiC复合材料力学性能的影响

Influence of Hot-Pressing Parameters on the Mechanical Properties of TiC Composites Reinforced with Carbon Fibers

采用真空加压烧结工艺制备了 2 0 % (体积分数 )短碳纤维增强TiC复合材料 (Cf/TiC) ,研究了加压烧结温度、烧结时间和烧结压力对力学性能的影响。烧结温度由 190 0℃提高到 2 10 0℃ ,复合材料的横向断裂强度和断裂韧度分别由 387MPa和 4 14MPa·m1/2 提高到 5 93MPa和 6 87MPa·m1/2 ,当烧结温度再提高到2 2 0 0℃ ,强度和韧性反而有所下降。加压压力由 2 0MPa提高到 35MPa时 ,横向断裂强度和断裂韧度分别由5 5 7MPa、6 41MPa·m1/2 提高到 6 0 2MPa和 6 92Mpa·m1/2 。当保温时间由 0 5h提高到 2h时 ,复合材料的横向断裂强度和断裂韧度分别由 5 6 8MPa、6 5 3MPa·m1/2 提高到 5 93MPa和 6 87MPa·m1/2 。Cf/TiC复合材料合适的烧结工艺是在 2 10 0℃、30MPa下烧结 1h ,所制备的材料的相对密度为 97 6 % ,弹性模量为 416GPa ,横向断裂强度为 5 93MPa ,断裂韧度为 6

In order to improve the mechanical properties of TiC ceramics, TiC composites containing 20 vol% short carbon fibers were prepared by vacuum hot-pressing. The hot-pressing technique for Cf/TiC composites was optimized. The investigated results of hot-pressing temperature of 1900-2200°C, pressure of 20-35 MPa and soaking time of 0.5-2 h on the flexural strength and fracture toughness show that the suitable technique condition is vacuum sintering at 2100°C under 30 MPa for 1 h. The transverse rupture strength of Cf/TiC composite prepared using the optimized technique is 593 MPa, the fracture toughness is 6.87 MPa &middot m1/2, the elastic modulus is 416 GPa and relative density is 97.6%.