【摘要】 对普通ＳｉＣ颗粒和钝化处理过的ＳｉＣ颗粒增强ＬＤ２铝复合材料的研究表明，颗粒经钝化处理后，几乎去除了很尖锐的部分，使颗粒呈近等轴状，但颗粒的形状对两种热处理态的复合材料（热挤出态和Ｔ６态）的断裂韧性ＫＱ均无影响，而热挤出态的复合材料ＫＱ低于Ｔ６态。断口和断裂路径的扫描电镜分析表明，Ｔ６处理提高了材料的屈服强度从而提高了材料的裂纹生成能，而同一热处理态的复合材料中，由于增强体之间间距过小等原因，基体受增强体胁迫，不能充分变形，降低了材料的裂纹扩展能，是复合材料低韧性的主要原因。更多还原

【Abstract】 LD2 aluminum alloy matrix composites reinforced with general SiC particles and blunted SiC particles were studied. The results showed that pointed particle corners have been almost eliminated after blunted. However, particle shape has no effect on fracture toughness of the composites with both heat treatments (T6 and hotextruded). Fracture toughness of the composites with T6 treatment is higher than that with hotextruded. Scanning Electron Microscope analyses on fractography and fracture path showed that the composites with T6 treatment have a higher crack nucleation energy due to the improvement of yield strength. In the composites with the same heat treatment, the matrix can not deform enough because the distance between reinforcement is too small and deformation of the matrix is localized by particle. Then the crack propagation energy is decreased. This is the main factor to the low fracture toughness of composites.更多还原