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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+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、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,从而防止了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,抗弯强度与断裂韧性都呈先升高后下降的趋势,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%、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、桥接及脱粘机制。
The CF / Al2O3-20% Ni cermet composites with carbon fiber (CF) volume fraction of 0, 5%, 10% and 15% were prepared by sol-gel and hot pressing sintering. The phase composition, morphology and composition distribution of CF / Al2O3-20% Ni composites were studied. The effects of CF content on the hardness, flexural strength and fracture toughness of CF / Al2O3-20% Ni composites were studied. SEM, The fracture morphology of CF / Al2O3-20% Ni composites was analyzed and the fracture mechanism was discussed. The results show that the CF / Al2O3-20% Ni composite with good dispersion of CF and Ni particles can be obtained by sol-gel method, and the surface of CF can be coated with α-Al2O3 protective film to prevent the formation of CF Burning during high temperature sintering. With the increase of the volume fraction of Cf, the hardness of CF / Al2O3-20% Ni composites decreased, the flexural strength and fracture toughness tended to increase firstly and then decreased. When the volume fraction of CF was 10%, the flexural strength and The fracture toughness of the CF / Al2O3-20% Ni composite alloy reached the peak value. Compared with the non-CF sample, the fracture toughness increased by 79% and 134% respectively. The addition of CF improved the strength and toughness of the CF / Al2O3-20% Ni composite. The toughening mechanism of CF / Al2O3-20% Ni composites prepared by this method is carbon fiber pull-out, bridging and debonding mechanism.