碳纤维增强Al_2O_3-20%Ni金属陶瓷复合材料的制备及组织性能

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/Al_2O_3-20%Ni金属陶瓷复合材料,采用XRD、SEM和EDS能谱分析了CF/Al_2O_3-20%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/Al_2O_3-20%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/Al_2O_3-20%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/Al_2O_3-20%Ni复合材料,并且可在CF表面包覆一层α-Al_2O_3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/Al_2O_3-20%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/Al_2O_3-20%Ni复合材料的强度和韧性得以改善。用此方法制备的CF/Al_2O_3-20%Ni复合材料的增韧机制为碳纤维的拔出、桥接及脱粘。

Fabrication and properties of carbon fiber reinforced Al2 O3-20%Ni metal-ceramic composites

The CF/Al2 O3-20% Ni metal-ceramic composites with 0%,5%,10% and 15% volume fraction of car-bon 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/Al2 O3-20%Ni hard-ness,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/Al2 O3-20% 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 temper-ature by the formation of α-Al2 O3 protective film layer on the CF surface.With the increase of volume fraction of CF,The hardness of the CF/Al2 O3-20% 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/Al2 O3-20%Ni composites.The toughening mechanism of CF/Al2 O3-20%Ni is CF pull out,bridge and disbonding.