Crack Initiation and Fracture of Metal Matrix Composites

An experimental study is performed to investigate the role of the composite architecture on the mircomechanisms of crack initiation and fracture of particle reinforced metal matrix composites (MMCs) under monotonic loading. In-situ tensile tests are performed in the scanning electron microscope (SEM), and the SEM-micrographs of different deformation stages are analyzed by an automatic local deformation measurement system. The procedure, which is described in Tatschl and Kolednik [

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], yields the local deformation and strain fields at the different stages with high accuracy and lateral resolution. In this way, the influence of the local composite architecture on the damage evolution in the material can be studied in great detail: the occurrence of first plasticity at particle corners, the formation of shear bands, particle fracture and decohesion, final fracture.