TiB2基金属陶瓷的显微结构与力学性能

以Fe-Ni-Ti-Al 为助烧剂, 用热压的方法制备了TiB2 基金属陶瓷。研究了烧结温度、烧结时间、助烧剂对材料显微结构和力学性能的影响, 初步分析了TiB2 基金属陶瓷的增韧机理。结果表明, 随着烧结温度的提高, 材料弯曲强度降低, 洛氏硬度升高;随着烧结时间延长, 弯曲强度出现峰值。SEM、EDS 观察表明, 助烧剂中的Ti 避免了Fe₂B、Ni₂₃B₆ 等脆性相的生成, Al 有除氧的作用。裂纹偏转和裂纹桥联是TiB2 金属陶瓷重要的增韧方式。

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF TiB2 CERMET

TiB_2 based cermet with Fe-Ni-Ti-Al as sintering aids was fabricated by hot-pressing.The effects of sintering temperature,holding time and sintering aids on microstructure and mechanical properties were investigated.The toughening mechanism of TiB_2 based cermet was analysed. Experimental results show that the bending strength of TiB_2 cermet decreases and the Rockwell hardness increases with sintering temperature rising up; a bending strength peak appears with holding time prolonged. According to the scanning electron microscope(SEM)and energy dispersive spectrometer(EDS)observation, Ti in sintering aids is essential for avoiding the formation of extremely brittle secondary borides such as Fe_2B and Ni_(23)B_6, while Al plays a deoxygen role. Crack deflection and crack bridging are important toughening ways of composite.