采用FAPAS法制备了超硬AlMgB14/TiB2复合陶瓷材料,分别采用扫描电镜(SEM)及能谱(EDS),X射线衍射仪分析添加超细TiB2第二相颗粒对复合材料微观形貌及韧性的影响;通过高温摩擦磨损试验分析了复合材料在25,300,500℃下的抗磨损性能及其摩擦学特征.结果表明,添加30％(质量分数)的微纳米级TiB2后,AlMgB14/TiB2复合材料的平均硬度达32.5 GPa,断裂韧性由未添加时的3.0 MPa·m1/2提高到3.95 MPa·m1/2;摩擦系数在室温及300℃时介于0.4～0.55之间,500℃时达0.65左右,磨损率1.27× 10-6～6.62× 10-6 mm3/(N.m).随着摩擦温度的升高,试样摩擦学性能发生变化,由于摩擦表面产生氧化物的润滑作用,摩擦系数在300℃时略有减小,磨损机理由室温时的磨粒磨损转变为高温下的粘着磨损脱落.
Field activated and pressure assisted synthesis (FAPAS) was used for preparing ultra-hard,super-abrasive A1MgB14/TiB2 composite ceramics.The influence of the ultra-fine TiB2 particles on the microstructure and toughness of the composite was analyzed by scanning electron microscopy (SEM),energy dispersive analysis (EDS) and X-ray diffraction (XRD).Wear resistance and tribological characteristics of the composite were analyzed at 25,300 and 500 ℃.The results show that the average hardness of A1MgB14/TiB2 composite materials with 30 wt％ ultra-fine grain addition reaches 32.5 GPa.The fracture toughness of the composite increases from 3.0 MPa·m1/2 without TiB2 particles addition to 3.95 MPa·m1/2.Friction coefficient ranges from 0.4 to 0.55 at room temperature and 300 ℃,and it reaches to 0.65 at 500 ℃.Wear rate ranges from 1.27×10-6 to 6.62×10-6 mm3/(N·m).With increasing the test temperature,the friction coefficient of the composite decreases slightly at 300 ℃ due to the lubrication of oxide formed on the surface of composite,and the wear mechanism changes from abrasive wear at room temperature to adhesive wear at high temperature.
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