Al_2O_3——TiC复合陶瓷断裂韧性K_(1c)测试方法的对比研究

Comparision of Methods of Determining Fracture Toughness K_(1c) of Al_2O_3——TiC Ceramics

以单边切口梁三点弯曲法、直接压痕法和桥式预裂纹三点弯曲法对Al_2O_3——TiC复合陶瓷刀具材料进行了断裂韧性K_(1c)值的测试,结果表明,对这种微米级颗粒尺寸的陶瓷材料,切口梁法的结果与桥式预裂纹法接近,基本反映了真实K_(1c)值,切口的钝化作用不明显;压痕法的结果比其它两方法偏低。本文从显微结构和断裂特性上对产生差异的原因和三种方法的适用性作了分析和评价。

This paper deals with the evaluation of three different methods of K_(1c) determination, namely Aingle-Edge Notched Beam Three Point Bending (SENB), Indentation and Bridge Crack-Inducing (BI). Four kinds of Al_2O_4——TiC ceramics with μm-grains were used as testing specimens. The experiments show that SENB can give out reasonable resuits of K_(1c) of these fine ceramics, as well as BI method, with little dependence on grain size The Indentation method raises a discrepancy with a lower K_(1c).