Fracture behavior of cylindrical porous alumina with pore gradient

In this study, laminated cylindrical porous alumina materials with a pore gradient along the radial direction are fabricated by combining a lower sintering temperature with the presence of an organic-former (PMMA particles). It has been proved that pore morphology can be controlled by the lamination method in the centrifugal molding technique. The fracture behavior of the porous laminated alumina with a pore gradient is investigated by using the ring compression testing. An analytical formula to account for the pore gradient is introduced to calculate fracture strength based on the curved beam theory. There are two types of fracture behavior, which are not related to the lamination process and vary with the amount of pore-former. In the case of the same porosity, a reduction in fracture strength is observed with increase in the number of laminated layers, and the minimum strength is found in continuous graded cylinders.