Experimental and numerical study of the elastic modulus vs temperature of debonded model materials

This work takes place in the frame of a general study dealing with the thermomechanical behaviour of industrial refractory materials. Because both the microstructural complexity of such materials and the strong influence of the elastic properties on the resistance to thermomechanical solicitations, the Young’s modulus of heterogeneous model material with simplified microstructure is studied in a first time. The studied materials are composed of a glass matrix surrounding alumina inclusions. These two materials exhibit a dilatometric dissension sufficiently large to induce, during a thermal cycle, thermal stresses able to damage the matrix/inclusions interfaces.The present study deals with the Young’s modulus variations according to the temperature in the case of model materials exhibiting debonding matrix/inclusions interfaces. It follows two other studies, at room temperature, devoted to the case of heterogeneous model materials exhibiting bonded and debonded interfaces respectively.The numerical simulation of the interfaces behaviour was carried out using the Abaqus FEM code whose the contact tool “debond” allows to account for the interface matrix damage during a thermal cycle. The rigidity of the modelled samples is obtained by simulating a pure tensile test under imposed stress then by using the Hooke’s law. The results show the strong influence of the meshing density at the crack tip so as that of the location of the initial damage regarding the loading direction during the tensile test.Moreover, samples fully similar to the numerical model were manufactured and their Young’s modulus was measured by using an ultrasonic technique. The comparison of the numerical and experimental results may be considered as satisfactory.