Fatigue Failure Behavior of Al_2O_3-SiO_2 System Bricks under Compressive Stress at Room and High Temperatures

摘要

The fatigue failure behaviors of high-alumina brick, agalmatolite brick and silica brick refractory materials were investigated at room temperature and high temperature. As a result, fatigue fracture lives at room temperature are almost the same with the order of high-alumina > agalmatolite > silica. In comparison with other inorganic materials, fatigue failure life in this work was slightly higher than that of silica glass and alumina ceramic. At high temperatures, it should be noticed that fatigue failure lives of the agalmatolite and silica bricks showed significant increases at the temperatures over 1 473 K. On the other hand, the high-alumina brick showed slight increase. The behavior of strain rate at high temperatures proved that the strain rate of the silica brick mainly increased as a result of crack growth, while crack growth in the high-alumina and aga matolite bricks increased as a result of creep deformation. Moreover, the reason why fatigue fracture at high temperatures increased in the agalmatolite and silica bricks was examined in more detail. It was deduced that the longer fatigue fracture lives at high temper atures were related to the generation of a slight amount of liquid phase. The degree, of how long fatigue fracture life would be, was estimated to be dependent on the wettability between the solid phase and liq uid phase; poor wettability elongated fatigue fracture life.