SiC_p－Si_3N_4基复合材料及其力学性能

研究了ＳｉＣ片晶（ＳｉＣｐ）强化Ｓｉ３Ｎ４基复合材料及其力学性能和增韧机理。研究结果表明，加入ＳｉＣｐ使Ｓｉ３Ｎ４材料的强度明显提高，并在ＳｉＣｐ含量（ＳｉＣｐ）＝０．２０（ＳｉＣｐ的体积分数）时有一峰值，ＳｉＣｐ加入量进一步增加使强度有较大降低。ＳＥＭ观察表明，裂纹偏转、片晶桥接是主要增韧机理，片晶拔出、基体细化等亦对断裂韧性的增加作出贡献，其作用与晶须增韧的机理相似。

SiC PLATELET-Si_3N_4 COMPOSITES AND THEIR MECHANICAL PROPERTIES

Mechanical properties and toughening mechanism of SiC platelet reinforced Si3N4(Y2O3-Al2O3 doped)composites were studied. The results show that strength of Si3N4 ceramics are obviously improved by the addition of SiC platelet and has a peak value at 9(SiCp) =0. 20 of SiC platelet, and then they are significantly decreased by further addition of SiC platelet. SEM observation shows that crack deflection and platelet bridging are the main toughing mechanisms, and platelet pull-out and reinforcement of the matrix grains also contributed to the improvement in the fracture toughness, which is similar to that of whisker toughening.