Investigation of the damage behaviour of refractory model materials at high temperature by combined pulse echography and acoustic emission techniques

The understanding of the thermomechanical behaviour of high temperature castables is essential for their use as linings in high temperature furnaces and refining vessels in the metallurgical, cement, and petrochemical industries. The increasing use of the finite element calculations for the prediction of the behaviour in using conditions requires the knowledge of mechanical properties at high temperature and especially for model materials. This work deals with the characterisation of the damage behaviour during thermal cycling of two two-phase refractory model materials when considering thermal expansion mismatch between the constituents. The acoustic emission technique (AE) and the ultrasonic pulse echography technique, both carried out at high temperature, were applied as non-destructive characterisation methods to monitor the damage extension within the materials submitted to thermal stress and to follow the evolution of the associated elastic properties, respectively.