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以MnO2与纳米TiO2为烧结助剂,通过1250℃的无压烧结制备出性能优异的MF(mullite fiber)/Al2O3复合材料。复合材料的弯曲强度与断裂韧性随MnO2与纳米TiO2含量的增加先增加后减小。当MnO2与纳米TiO2掺量分别为3%(质量分数,下同)和1.8%时,MF/Al2O3复合材料的抗弯曲强度与断裂韧性分别达到568MPa和6.8MPa·m1/2。Mn4+和Ti4+扩散到MF和Al2O3基体的界面处,改善了MF和Al2O3基体之间的界面结合强度,复合材料断裂时,产生纤维的拔出与脱粘、裂纹偏转以及纤维的桥联等作用,消耗大量的断裂能,大大提高了复合材料的抗弯曲强度与断裂韧性。
MnO2 and nano-TiO2 were used as sintering aids to prepare MF (mullite fiber) / Al2O3 composite with excellent performance through pressureless sintering at 1250 ℃. The flexural strength and fracture toughness of the composites increase first and then decrease with the increase of MnO2 and nano-TiO2 content. The flexural strength and fracture toughness of MF / Al2O3 composites reached 568 MPa and 6.8 MPa · m1 / 2, respectively, when the contents of MnO2 and nano-TiO2 were 3% (mass fraction) and 1.8% respectively. Mn4 + and Ti4 + diffuse into the interface between MF and Al2O3 matrix, the interfacial bonding strength between MF and Al2O3 matrix is improved, and the pulling and debonding of fiber, crack deflection and bridging of fibers occur when the composite material is broken, Consume a large amount of fracture energy, greatly improving the composite material flexural strength and fracture toughness.