Fracture behavior of hybrid platelet-fiber alumina preforms

We studied the fracture behavior of alumina platelet preforms, with a global porosity of 80%, containing a weight fraction of short fibers varying between 0 and 50%. This addition of fibers leads to an increase in the work of fracture of the preform. An experimental method was set up to obtain a controlled rupture of these specimens and a load–displacement curve which allowed us to measure the increment of rupture energy due to the fiber pull-out. Experimental curves were interpreted by means of a micromechanical model developed initially for the study of the fracture behavior of ceramic matrix composites. This led us to estimate an equivalent friction stress between fibers and platelets of the order of 0.04 MPa.