氧化锆陶瓷室温循环疲劳行为研究

Research on the Cyclic Fatigue Behavior of Zirconia Ceramics at the Room Temperature

对一种氧化锆陶瓷材料的室温循环疲劳行为进行了研究。陶瓷材料通过干压、冷等静压成型,无压烧结。循环疲劳实验采用四点弯曲法。试验结果表明,该氧化锆陶瓷材料的循环疲劳寿命与循环应力最大值和循环应力幅值在双对数坐标下皆为线性关系,循环应力最大值增大,循环疲劳寿命降低;循环应力幅值增大,疲劳寿命也降低。但循环疲劳寿命对循环应力最大值的依赖程度要大于对循环应力幅值的依赖。循环疲劳寿命与裂纹的初始尺寸在双对数坐标下也呈线性关系,随着裂纹初始尺寸增加,循环疲劳寿命降低。试验结果同时表明,回火消除残余应力试样的循环疲劳寿命都远大于未回火试样。计算表明,该种氧化锆陶瓷的裂纹缓慢扩展指数大约在8～13之间。

Cyclic fatigue behavior of zirconia ceramics material was researched at the room temperature. ZrO2 powders were shaped through cold isostatic pressing after dry pressing and then sintered by pressless sintering. Four points flexural method was used in the cyclic fatigue experiments. The experimental results show that the relationship between cyclic fatigue life of the zirconia ceramics and both the maximum cyclic fatigue stress and the magnitude of the fatigue stress is linear in the bi-logarithmic figures. When the maximum fatigue stress increases, the cyclic fatigue life decreases. When the cyclic fatigue stress increases, the cyclic fatigue life also decreases. But the cyclic fatigue life of the zirconia ceramics depends on the maximum cyclic fatigue stress mainly. The relationship between the cyclic fatigue life and the initial crack length is also linear in the bi-logarithmic figures and the cyclic fatigue life decreases when the initial crack length increases. It is found that the cyclic fatigue life of annealed samples is much larger than the unannealed samples under the same experimental conditions. Evaluated results show that the crack growth exponent of the zirconia ceramics is about 8-13.