Effect of composition and annealing temperature on the mechanical properties of a vitrified waste

The microhardness and indentation fracture toughness of a vitrified industrial waste, in the form of ash, were characterized by the method of static indentation test. These properties were investigated as a function of composition and thermal treatment conditions. To further understand the influence of the constitutive oxides, additional measurements were made in a series of synthetic products, where a mixture of iron and lead oxides was used as a substitute for the ash. The underlying deformation mechanisms controlling the mechanical properties of such complex systems as determined by static indentation tests are discussed. It was found that plasticity, in the amorphous products, is mainly governed from the silica content, even in the cases where silica is not found in sufficient quantity in order to build an extended three-dimensional vitreous network. On the other hand, the morphology of the separated crystalline phases is the dominant factor affecting plasticity in the glass-ceramic products.