【摘要】 采用一次粒径分别为 10nm和 15nm的α Al2 O3 和SiC粉体为原料 ,制备了Al2 O3 /SiC纳米陶瓷复合材料·纳米SiC颗粒明显抑制Al2 O3 基体晶粒的长大 ,SiC体积分数超过 4 %时 ,材料的断裂方式由沿晶断裂变为穿晶断裂·随SiC含量的增加 ,Al2 O3 /SiC纳米复合材料的硬度增大·材料的弯曲强度和断裂韧性在SiC体积分数为 5 %时达到最大值·最大三点弯曲强度和断裂韧性分别为 6 4 1MPa和 4 7MPam1/2 ,明显高于热压单相Al2 O3 陶瓷 (344MPa和 3 1MPam1/2 ) ·复合材料的强化主要来源于内晶颗粒残余应力强化和晶粒细化强化更多还原

【Abstract】 Al 2O 3/SiC ceramic nanocomposites were fabricated from nanocrystalline α Al 2O 3 (10?nm in diameter) and SiC (15?nm in diameter) powders. Nanocrystalline SiC particles restrain remarkably the grain growth of the Al 2O 3 matrix. When SiC content exceeds 4%, fracture mode of the composites is changed from intergranular to transgranular. Hardness of the Al 2O 3/SiC composites increases with increasing SiC content. Both three point bending strength and fracture toughness reach the maximum values at a SiC content of 5%. The maximum three point bending strength and fracture toughness are 641?MPa and 4 7?MPa m 1/2 , respectively, higher than those of the hot pressed Al 2O 3 ceramic (344?MPa and 3 1?MPa m 1/2 ). Strengthening mechanisms are interpreted mainly due to the intragranular particle residual stress and the grain refining.更多还原