Effect of metal-layer structure on the mechanical properties of multilayer metal-ceramic composites. I. fracture energy

The effect of the metal-layer geometry and of the interface structure on the fracture toughness of multilayer metal-ceramic composites is examined. The samples are produced by free sintering of layups consisting of alternating metal and ceramic layers. The ceramic layers are prepared by rolling fine pyrophyllite powders into strips. The metal layers are prepared from stainless steel fabric. Before sintering, the layups are pressed across and along the layers. The samples show 24-25% residual porosity after the free sintering of layups containing 15 vol.% metal phase at 1000A degrees C. The fracture energy of the samples is determined. Their microstructure is examined. It is shown that the use of metal fabric substantially increases the fracture energy of composites. This is due to the developed skeleton structure of multilayer ceramic-metal fabric composites, which weakens the adverse effect of the residual porosity and sometimes poor adhesive contact between the metal and ceramic components on fracture toughness.