Modellierung der Eigenschaften und des Versagens von Metallmatrixverbundwerkstoffen mit lamellarer Struktur

Metal matrix composites (MMC) based on ceramic performs can be easily realized with a high ceramic content. Additionally, it is possible to selectively reinforce a component only where it is necessary. They exhibit advantages such as a high specific stiffness and low thermal expansion due to the ceramic reinforcement which is continuous in three dimensions. Within a joint research project a new type of MMC was produced by infiltrating freeze cast alumina performs with Al alloys. The resulting MMC has a microstructure which contains large statistically oriented domains of parallel ceramic lamellae. The current contribution describes how this microstructure can be implemented in a micromechanical model using a multiscale approach. The program "OOF2" (National Institute of Standards and Tech nology, Washington D.C.) was used to convert microstructures into a finite element mesh. The possibility of interfacial decohesion was included into the model by introducing cohesive elements into the FE mesh at the phase boundaries. Based on such meshes, thermal residual stresses, stress-strain and thermal expansion behaviour were predicted by FE calculations. The effects of different fracture energies of the metal-ceramic interface and of different lamellae orientations on the failure behaviour were investigated.