颗粒形状及基体热处理对SiCp/LD2断裂韧性的影响

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的断裂性ＫＱ均无影响，而热挤出态的复合材料ＫＱ低于Ｔ６态。

Effects of Particle Shape and matrix heat Treatment on Fracture Toughness of SiCp/LD2 Composites

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.