【摘要】 利用热压法制备了（LaNbO₄+ZrO₂）/MoSi₂复合陶瓷材料,通过扫描电镜、图像分析仪、X射线衍射仪分析了其显微组织、物相和断裂特征,测算了其显微硬度、晶粒尺寸、孔隙率和断裂韧度。结果表明:该复合材料与单相MoSi₂相比,其晶粒明显细化,致密性很好,硬度值略有增大;LaNbO₄、ZrO₂颗粒的协同复合作用引起断裂机制由穿晶断裂为主向沿晶断裂为主转变,使复合材料的韧性显著提高,这主要与晶粒细化、致密性提高、ZrO₂纳米颗粒的相变增韧、裂纹偏转、微裂纹区增韧以及LaNbO₄应力激发的畴结构切换增韧机制有关。更多还原

【Abstract】 (LaNbO₄+ZrO₂)/MoSi₂ composite ceramics were prepared by hot-pressing sintering.The microstructure and fracture characteristics of composites were analyzed by means of scanning electron microscope, image analysis instrument and X ray diffractometer.The microhardness,grain size,porosity and fracture toughness were measured.The grain of （LaNbO₄+ZrO₂）/MoSi₂ composite sample is obviously fine compared with that of MoSi₂ sample.The compactness of composite is excellent with microhardness increased.LaNbO₄ assist with ZrO₂ particles caused the change from transgranular to intergranular fracture mechanism,which greatly improved the toughness of MoSi₂.These might he related to the fine crystal grain,improved compactness,phase transfer toughening,crack deflect,microcrack toughening of ZrO₂ nanopartides and domain structure transfer of LaNbO₄ particles.更多还原