Effect of relative density on the compressive flow behaviour of cordierite and cordierite: mullite honeycombs

摘要

Monolithic ceramic materials, especially the materials that are suitable for making honeycombs, have not been extensively used in many structural applications due to their inherent brittleness. However, the honeycomb structures made from these materials have recently become attractive for certain structural applications and hence, are investigated for their compressive flow behaviour at ambient and elevated temperatures. In this study, cordierite (2MgO2Al_2O_35SiO_2) and cordierite:mullite (2MgO2Al_2O_35SiO_2:3Al_2O_32SiO_2) honeycombs with the relative densities of 0.3 and 0.7 have been evaluated to determine their compressive flow behaviour. For the sake of comparison, solid specimens of cordierite with a relative density of 1.0 were also prepared and subjected to compressive testing. The results obtained from these solid specimens were compared with those of the honeycombs to bring out the property advantages that accrue by adopting to the honeycomb technology. Unlike solid specimens, the honeycombs were found to exhibit significant extent of stable crack extension and hence, a considerable increase in the toughness. Further the results from high temperature compressive testing have revealed that the compressive strength increases with increase in test temperature, exhibiting a maximum peak compressive strength at 1073 K for cordierite honeycombs and at 1273 K for cordierite:mullite honeycombs.