碳纤维增强Al2O3-20% Ni金属陶瓷复合材料的制备及组织性能
Fabrication and properties of carbon fiber reinforced Al2O3-20% Ni metal-ceramic composites

采用溶胶-凝胶+热压烧结法制备了碳纤维（CF）体积分数分别为0%、5%、10%、15%的CF/Al2O3-20% Ni金属陶瓷复合材料，采用XRD、SEM和EDS能谱分析了CF/Al2O3-20% Ni复合材料的物相组成、组织形貌及成分分布，并研究了CF含量对CF/Al2O3-20% Ni复合材料硬度、抗弯强度和EDS断裂韧性的影响，通过SEM分析了CF/Al2O3-20% Ni复合材料的断口形貌并探讨了断裂机制。结果表明：采用溶胶-凝胶法可获得CF分散良好、Ni颗粒分布均匀的CF/Al2O3-20% Ni复合材料，并且可在CF表面包覆一层α-Al2O3保护膜，从而防止CF在高温烧结过程中的烧损。随着CF体积分数的增加，CF/Al2O3-20% Ni复合材料的硬度降低，抗弯强度和断裂韧性都先升高后下降，当CF体积分数为10%时，抗弯强度和断裂韧性均达到峰值，相对不含CF试样分别提高了79%和134%，CF的加入使CF/Al2O3-20% Ni复合材料的强度和韧性得以改善。用此方法制备的CF/Al2O3-20% Ni复合材料的增韧机制为碳纤维的拔出、桥接及脱粘。 The CF/Al2O3-20% Ni metal-ceramic composites with 0%, 5%, 10% and 15% volume fraction of carbon fiber (CF) were prepared by sol-gel method and hot-pressing sintering. The phase composition,surface and fracture morphology were analyzed by XRD, SEM and EDS. The effect of CF content on CF/Al2O3-20% Ni hardness, bending strength, fracture toughness was studied. The fracture morphology of composites was analyzed by SEM and its mechanism was discussed. The results show that CF/Al2O3-20% Ni composites with well dispersed CF and evenly distributed Ni particles was obtained, and can prevent the loss CF in the sintering process at high temperature by the formation of α-Al2O3 protective film layer on the CF surface. With the increase of volume fraction of CF, The hardness of the CF/Al2O3-20% Ni composites reduce, and its bending strength and fracture toughness first increase and then decrease. When the CF volume fraction is 10%, the bending strength and fracture toughness reach the maximum values, which increase by 79% and 134%, respectively, compared with the composites without CF. The addition of CF improves the strength and toughness of the CF/Al2O3-20% Ni composites. The toughening mechanism of CF/Al2O3-20% Ni is CF pull out, bridge and disbonding. 国家自然科学基金（51461029）；兰州理工大学红柳青年教师培养计划（201203）