热压烧结TiB_2-VB复合陶瓷的结构与性能

Microstructure and Mechanical Properties of Hot-pressed TiB_2-VB Composites

采用热压烧结法制备了TiB2-VB复相陶瓷,系统研究了VB对TiB2陶瓷机械性能与显微结构的影响。实验发现VB的添加能够有效提高TiB2陶瓷的机械性能,TiB2-8%VB的样品在1800℃热压烧结1 h,其弯曲强度、断裂韧性与维氏硬度分别达到(767±39)MPa、(5.23±0.14)MPa.m1/2和(20.44±0.25)GPa。物相分析表明VB与TiB2在烧结过程中形成了固溶体,显微结构研究发现VB的加入明显抑制了TiB2晶粒尺寸的长大,使材料的烧结密实度提高。

In this paper, TiB2-VB composites are prepared by hot pressing. The influences of composition and process parameters on mechanical properties of composites are researched. The rdationship between microstructure and mechanical properties is analyzed. It is shown that the mechanical properties of TiB2 composites can be improved by the introduction of VB. In the sample of TiB2-8%VB hot pressed at 1 800℃ for 1 h, the maximum values of bending strength, fracture toughness and Vickers hardness are obtained as （767 ± 39） MPa, （5.23 ± 0.14 ） MPa·m^1/2 and （ 20.44 ± 0.25 ） GPa, respectivdy. Through the phase and microstructure analyses, the formation of solid solution between TiB2 and VB is demonstrated, which is beneficial to hinder the grain growth of TiB2.