Abstract

Refractories are heterogeneous materials designed to operate in harsh working environments which sometimes lead to their premature failure. Therefore, it is necessary to enhance their properties to ensure consistent furnace performance and operator safety. Among these properties, the thermal shock resistance of refractories is a parameter of significant interest which is known to be closely related to their mechanical behaviour. In fact, an existing network of micro-cracks within the microstructure of refractories often leads to non-linear mechanical phenomena around the crack tip which are beneficial for their crack propagation resistance and thus, their thermal shock resistance.

In the present study, refractory materials with a non-linear mechanical behaviour were chosen in order to highlight their fracture behaviour, with regard to their microstructure, by using Digital Image Correlation (DIC). The direct measurement of displacement fields between digital images of the reference state and the deformed one has provided valuable information on material deformation during loading, especially at the vicinity of the crack tip where non-linear phenomena take place. Therefore, the aim of this work is to investigate the fracture behaviour of refractories through DIC by using a refined DIC process based on a material transformation taking into account a discontinuity of displacement.

As highlighted by the results, the coupling of DIC with mechanical tests commonly applied to refractories (Wedge splitting test, Brazilian test and bending) has proven to be effective in characterizing the mechanical behaviour of these materials. The set of measured data can be used as a validation tool for numerical models and thus, bridge the gap between experiments and simulations.