Deformation and fracture of alumina ceramics with hierarchical porosity

Abstract

the compression behavior of Al2o3 ceramics with a hierarchical pore structure was studied. the hierarchical pore structure included the pores of three types: coarse porosity with a size of 80 to 100 μm, fine porosity with a size of 14 to 15 μm, and intermediate interblock porosity comprised of elongated (110-120 μm) porous microchannels formed as a result of zonal isolation during sintering. it is shown that the obtained hierarchical porous structure causes the formation of a hierarchical deformation structure in the volume of ceramics and leads to a decrease in the extent of destruction processes from the macroscopic scale in the case of unimodal ceramics to the microscale destruction comparable with the sizes of the blocks formed during sintering. At fixed values of the pore space, the studied ceramics with hierarchical pore structure shows a noticeably higher compressive strength as compared to the ceramics with a unimodal porosity.

The study of the behaviour of the ceramic composites ZrO2(MgO)-Al2O3 in a wide temperature range

“…The increase in temperature leads to a decrease in the average porosity. In the works [23][24][25] it is confirmed both by methods of mathematical modeling and full-scale experiments that the increase in porosity leads to a sharp decrease in the compressive strength. All these works are carried out under normal conditions.…”