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选用莫来石纤维(MF)和纳米ZrO2为增强体制备了MZTA复合增韧氧化铝陶瓷复合材料。通过设计正交试验讨论了MF含量、nano-ZrO2含量、烧结温度、保温时间等因素对材料力学性能的影响,利用扫描电镜、能谱分析仪研究了陶瓷复合材料的微观结构与性能的关系。结果表明:当莫来石纤维和纳米ZrO2的质量分数分别为10%,烧结温度为1550℃,保温时间为30 min,陶瓷复合材料的抗弯强度、断裂韧性分别达到712 MPa、10.05 MPa.m1/2,与纯Al2O3陶瓷相比晶粒细化、力学性能显著提高;纤维的拔出、桥联、裂纹扩展路径偏转、沿晶断裂等消耗了大量的断裂能、缓和了裂纹尖端的应力是材料断裂韧性提高的主要原因。
MZTA composite toughening alumina ceramic composites were prepared by using mullite fiber (MF) and nano-ZrO2 as reinforcements. The effects of MF content, nano-ZrO2 content, sintering temperature, holding time and other factors on the mechanical properties of the composites were discussed through the design of orthogonal experiment. The relationship between the microstructure and properties of the ceramic composites was investigated by SEM and EDS. The results show that the flexural strength and fracture toughness of ceramic composites reach 712 MPa and 10.05 MPa.m1 respectively when the mass fraction of mullite fiber and nano-ZrO2 is 10%, the sintering temperature is 1550 ℃ and the holding time is 30 min. / 2. Compared with the pure Al2O3 ceramic, the grain refinement and the mechanical properties were significantly improved. The fiber pull-out, bridging, crack propagation path deflection, intergranular fracture and so on consumed a large amount of fracture energy and relaxed the crack tip stress The main reason for the increase of fracture toughness of materials.