1991 Volume 40 Issue 454 Pages 863-868
In order to study the applicability of a unified estimation method on evaluation of strength for porous Al2O3 ceramics used as refractories, various kinds of bending fracture tests, such as fast fracture, dynamic fatigue, cyclic fatigue and static fatigue tests, were carried out on 3 kinds of porous Al2O3 specimens. The main testing temperature conditions were room temp. and 1200°C in atmosphere.Other temperature conditions of 600, 800, 1000, 1100°C were added only in fast fracture tests. The stength data obtained were analyzed by use of a unified estimation method. The temperature dependence data were studied through Arrhenius plots. The results obtained were as follows:
(1) The unified estimation method can be applied to the strength evaluation of porous Al2O3 at 1200°C as well as room temperature.
(2) The temperature dependence of fracture strength was distinctly different below and above 1000°C. Above 1000°C, the fracture strength decreased rapidly with elevating temperature. But below 1000°C, the fracture strength was about constant up to 500°C and then increased slightly.