Modified four-point bending specimen for determining the interface fracture energy for thin, brittle layers

摘要

A well-known four-point bending test has beenmodified such that the critical energy release rate gc fordelaminating cracks propagating at the interface of a thin, brittlelayer bonded to a substrate can be measured. The energy releaserate g required for crack delaminating at those interfaces isobtained by attaching a stiffening layer to the layer system.Another advantage of this modification is that segmentation ofthe layer and plastic deformation of the substrate during bendingare avoided. The interface fracture energy gc of a plasma sprayedZrO2-ceramic layer on a lame sprayed high alloyed steel substratehas been measured.