Compressive fatigue behaviour of refractories with carbonaceous binders

Furnace linings of magnesia-carbon and micro-porous carbon bricks experience cyclic compressive loads. An experimental programme has been carried out to assess the sensitivity of these materials to compressive fatigue failure. Next to room temperature tests, a number of high temperature tests have been performed. Results of the fatigue tests have been analysed together with the data of the monotonic stress–strain loading and creep tests. Compressive fatigue failure has been seen in both the materials. The less brittle material has shown lower fatigue life. The curve relating the fatigue strains with the amount of cycles has been of classical sigmoid shape with three phases. The strain rates of the secondary (linear) phase have shown good correlation with the number of cycles to failure. The grain–matrix interface has been found to play the critical role in the initiation and propagation of the fatigue cracks.