超细TiB2对AlMgB14-TiB2力学性能及抗高温磨损性能的影响

Effects of ultra-fine grained TiB2 on AlMgB14-TiB2 mechanical properties and resistance to high-temperature wear properties

摘要:

本文采用FAPAS法制备了超硬AlMgB14∕TiB2复合陶瓷材料，分别采用扫描电镜SEM及能谱分析EDS，X射线衍射仪分析了添加超细TiB2第二相颗粒对微观形貌及复合材料韧性的影响；并通过高温摩擦磨损试验表征和分析了复合材料在25℃，300℃，500℃下的抗磨损性能及其摩擦学特征。研究结果表明，添加30 wt% 的纳米级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3.0MPa? m1/2提高到3.95MPa? m1/2 ；摩擦系数在室温及300℃时介于0.4-0.5之间，500℃时达0.65左右，磨损率1.27?0-6 mm-3/（N? m）~6.62?0-6 mm-3/（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，300℃时摩擦系数有所减小，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。

Abstract:

In this paper, the field activated and pressure assisted synthesis (FAPAS) were used for preparing the ultra-hard, super-abrasive AlMgB14∕TiB2 composite ceramic. We analyzed how the ultra-fine TiB2 particles influence microstructure and toughness of samples by using scanning electron microscopy (SEM), energy dispersive analysis (EDS) and X-ray diffraction (XRD) respectively. The wear resistence and tribological behavior of AlMgB14∕TiB2 composite materials at 25℃, 300℃,500℃ were characterized throughing high-temperature friction and wear test. The results show that the average hardness of AlMgB14∕TiB2 composite materials reached 32.5 GPa after adding 30 wt% submicron scale TiB2 particles. The fracture toughness was seen to increase from 3.0 to 3.95MPa? m1/2. Friction coefficient ranged from 0.4 to 0.5 at room temperature and 300℃ , this figure exhibited approximately 0.65 in the case of 500℃ sliding operation. The specific wear rate ranged from 1.27?0-6 mm-3/（N?m）to 6.62 mm-3/（N﹒m）.With increasing the test temperature, The tribological properties of AlMgB14∕TiB2 composite materials changed, As a result of the friction surface oxide lubrication, friction coefficient decreased at 300℃，the wear mechanism from abrasive wear at room temperature to adhesive wear .