The morphology of the cracks during bending of a notched bar does not seem to be particularly affected by the presence of nanoparticles or glass phase in the composition (FIGURE ). The crack always follows the interfaces between the alumina platelets. The presence of the glass phase and nanoparticles however increases the reinforcement noted on the force-displacement curves (FIGURE ) and improves the mechanical properties (FIGURE and FIGURE ). This is probably first explained by the reduction of porosity during sintering. This hypothesis is further supported by the better properties of AP-Zt-HP compared to AP-Zt; the higher maximum pressure during the sintering increases the final relative density and the fracture properties of the material, as shown in FIGURE . It should be noted, however, that between AP ng -Zt and AP-Zt-HP, the strength is higher for AP ng -Zt despite similar porosity. The glass phase and the nanoparticles therefore tend to improve the fracture properties of the material, certainly by reducing the porosity, but not only. They could also improve the sintering quality possibly resulting in a better adhesion between alumina platelets.