ZrB2在Al2O3-ZrB2复相陶瓷中的增韧性能

Toughening Effect of ZrB2 in Al2O3-ZrB2 Nanocomposite Ceramics

摘要:

常压烧结制备了Al2O3和20wt%ZrB2/Al2O3复合陶瓷，用XRD和金相显微镜、SEM分析了其相组成、微观结构、断裂形貌，并用压痕法计算了陶瓷的断裂韧性。结果表明：Al2O3陶瓷自1500℃开始其相对密度超过99%，维氏硬度达到1897HV，断裂韧性为5.2?.3MNm-3/2；20wt%ZrB2/Al2O3复合陶瓷在1450℃时相对密度超过98%，维氏硬度达到1807HV，断裂韧性为6.7?.2MNm-3/2。微观形貌观察表明，ZrB2/Al2O3复合陶瓷韧性的增加是由于弥散分布的ZrB2在Al2O3陶瓷基体中起到遏制裂纹扩展和钉扎双重作用的结果。

Abstract:

The Al2O3-ZrB2 nanocomposite ceramics were prepared and the mechanical properties of the process parameters’ effect were studied. The results showed that: Among the various values of sintering temperatures applied, a maximum Vickers hardness of 1897HV and high reliability were attained at 1500 癈 and at atmosphere sintering. In addition, the sample was not well densified under the sintering temperature. Scanning electron microscopy (SEM) showed that fine ZrB2 particles dispersed and pinning at grain boundaries to inhibit grain boundary movement effectively. While larger ZrB2 particles distributed between A12O3 particles uniformly and occupy A12O3 particles grow space to hinder the matrix grains, which greatly promoted the densification of the ceramic, improving the microstructure. Fracture morphology indicates that trans-granular fracture was occurred, the ceramic material having high toughness.