气压烧结TiB2-Al2O3复相陶瓷的显微结构与力学性能

以2.5%(质量分数,下同)Ni为助烧剂,用气压烧结方法分别制备了含20%,30%和50%Al2O3的TiB2-Al2O3复相陶瓷.通过扫描电镜观察样品的形貌,并研究了Al2O3含量对材料显微结构和力学性能的影响.结果表明:金属Ni能有效地促进材料的致密化;随着Al2O3含量的增加,材料的致密度、抗弯强度和断裂韧性增加,弹性模量出现峰值,Vickers硬度降低,Rockwell硬度变化不大.在加入30%Al2O3时,得到了显微结构均匀,性能较好的TiB2-Al2O3复相陶瓷,其抗弯强度可达520MPa,弹性模量达339GPa,Rockwell硬度达92.6.

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF GAS PRESSURE SINTERING TiB2-Al2O3 MULTIPHASE CERAMICS

TiB2-Al2O3 multiphase ceramics, containing 20%, 30% and 50% (mass fraction, the same below) Al2O3, were fabricated by the gas pressure sintering method, using 2.5% Ni as an assistant. The microstructure of the samples was observed by scanning electron microscopy, and the effects of the Al2O3 content on the microstructural and mechanical properties were investigated. The results show that the densification is effectively accelerated by adding Ni. With the increase of the Al2O3 content, the density of the ceramic,the bending strength and the fractural toughness are all enhanced; the Young's modulus appears with a peak value, the Vickers hardness decreases, and the Rockwell hardness has little change. The TiB2-Al2O3 ceramic with 30% Al2O3 shows more promising properties, with a bending strength of 520 MPa, a Young's modulus of 339 GPa, and a Rockwell hardness of 92.6.