The effect of microstructures, such as grain size and internal pores, on the fatigue behavior of aluminum titanate (AT, Al2TiO5) ceramics was investigated at room temperature and 973 K. When the average grain size of the AT ceramics was decreased from 22 to 13 μm, the flexural strength was approximately doubled at both temperatures. The decrease in the grain size is considered to reduce the size and amount of microcracks present at the grain boundaries. Fatigue deterioration of the ceramics was accelerated by applying cyclic stress. The cyclic fatigue behavior of the ceramics with smaller grains suggested control by a “grain bridging degradation mechanism” at both temperatures. However, that of the ceramics with larger grains was governed by the fatigue mechanism, depending on the testing temperatures. There was little effect from internal pores on the cyclic fatigue behavior of the AT ceramics at room temperature. On the other hand, at 973 K, the lifetime of the cyclic fatigue was decreased due to the presence of pores.
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机译：研究了晶粒大小和内部孔隙等微观结构对钛酸铝（AT，Al 2 TiO 5 ）陶瓷在室温和973下的疲劳行为的影响。 K.当AT陶瓷的平均晶粒尺寸从22μm减小到13μm时，在两个温度下的抗弯强度都大约增加了一倍。晶粒尺寸的减小被认为是减小了晶粒边界处存在的微裂纹的尺寸和数量。施加循环应力会加速陶瓷的疲劳劣化。建议在两个温度下通过“晶粒桥接降解机理”来控制晶粒较小的陶瓷的循环疲劳行为。然而，取决于测试温度，具有较大晶粒的陶瓷是由疲劳机理决定的。在室温下，内部孔隙对AT陶瓷的循环疲劳行为几乎没有影响。另一方面，在973 K时，由于存在气孔，循环疲劳寿命降低。
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