Influence of Loading rate and Speciment Height on Flexural Strength of AL sub 2O sub 3 at High Temperatures

摘要

In this paper, the influence of loading rate and specimen height on flexural strength fo AL sub 2 O sub 3 at high temperatures is studied by three-point bending method. The experimental results show that the flexural strength of AL sub 2O sub 3 decreases with specimen height increasing at room temperature, and it trends to stabilize when height increases to a cetain degree, while the flexural strength fo AL sub 2O sub 3 variate unapparently at high temperature with height increasing. There exists a critical loading rate R sub c when loading rate R is less than R sub c, the flexural strength of AL sub 2O sub 3 increasees with loading rate increasing and it drops sharply when loading rate is more than R sub c. The sensitivity fo flexurl strength to the loading rate decreases with elecating temperatures.