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以Y2 O3-Al2 O3和MgO -Al2 O3为烧结助剂体系 ,研究了烧结助剂体系及其含量对Cf/SiC复合材料密度与力学性能的影响。结果表明 ,以Y2 O3-Al2 O3为烧结助剂时 ,复合材料的力学性能优于烧结助剂为MgO -Al2 O3时复合材料的力学性能。当烧结助剂为Y2 O3-Al2 O3时 ,随着烧结助剂含量的增加 ,复合材料力学性能不断提高 ,断裂韧性在烧结助剂含量为 12 %时达到最大值 14.83MPa·m1/ 2 。进一步增加烧结助剂的含量 ,复合材料的抗弯强度虽有提高 ,但断裂韧性急剧降低。烧结助剂含量超过 15%后 ,抗弯强度也急剧降低。结果同时证明 ,复合材料的断裂行为取决于纤维 /基体间的界面结合强度 ,即纤维 /基体间的界面结合情况是决定纤维增强陶瓷基复合材料力学性能的关键因素
The influence of sintering aid system and its content on the density and mechanical properties of Cf / SiC composites was investigated by using Y2 O3-Al2 O3 and MgO-Al2 O3 as sintering aids. The results show that the mechanical properties of the composites are better than those of the sintering aids of MgO-Al 2 O 3 when Y 2 O 3 -Al 2 O 3 is used as the sintering additive. When the sintering aid is Y2 O3-Al2 O3, the mechanical properties of the composites increase with the increase of sintering additives, and the fracture toughness reaches 14.83 MPa · m1 / 2 with the sintering aid content of 12%. Further increase the content of sintering aids, although the flexural strength of the composites increased, but the sharp decline in fracture toughness. When the content of sintering aids exceeds 15%, the bending strength also decreases drastically. The results also show that the fracture behavior of the composites depends on the interfacial bonding strength between the fibers / matrix, that is, the interfacial bonding between the fibers / matrix is the key factor that determines the mechanical properties of the fiber reinforced ceramic matrix composites