Ceramic matrix composites (CMCs) are structural materials, which have useful properties that combine high strength at high temperatures with moderate toughness. Carbon fibers within a matrix of carbon and silicon carbide, called C/C–SiC, are a particular class of CMC noted for their high oxidation resistance. Here we use a combination of four-point bending and X-ray radiography, to study the mechanical failure of C/C-SiC CMCs. Correlating X-ray radiographic and load/displacement curve data reveals that the fiber bundles act to slow down crack propagation during four-point bending tests. We attribute this to the fact that strain energy is expended in breaking these fibers and in pulling fiber bundles out of the surrounding matrix material. In addition, we find that the local distribution and concentration of SiC plays an important role in reducing the toughness of the material.

Meet the technical specifications defined by the designengineering department is a critical factor to haveof a good performance during the normal life cycle of heavy mining equipment. This study was done to determine how the repair process carried out in order to recover structuralcomponents that did not meet the proper quality criteria after the inspection process,can alter the microstructure and the mechanical properties of the product used in the construction of heavy miningequipment.

As the repair process can be donenot only once, but twice and until three times using a manual GMAW process, this study was carried out under controlled conditions and using similar process parameters as those used in the manufacturing process. A set of four specimens were prepared, one without any repair, and the other three with one, two and three repairs. In order to evaluate the sanity of the welded unions and also the materials behavior of each one of the specimens, tensile, microhardness, macroetch, charpy, and metallographic testswere carried out

Cet article discute d'une stratégie pour piloter un essai mécanique en utilisant la corrélation d'images. Un asservissement en cascade est développé en utilisant unalgorithme de corrélation sub-pixel permettant l'évaluation d'unedéformation moyenne dans une région d'étude pour piloter unemachine électro-hydraulique asservie. Une analyse a priorid'incertitude est validée a posteriori avec des mesures obtenueslors d'un essai mécanique. Le système développé est utilisé pourla conduite d'un essai de traction sur acier.