An experimental-computational approach to the investigation of damage evolution in discontinuously reinforced aluminum matrix composite

A combined experimental-computational approach to study the evolution of mi croscopic damage to cause failure in commercial SiC particle reinforced DRA s is dealt with. Determination of aspects of microstructural geometry that are most critical for damage nucleation and evolution forms a motivation fo r this work. An interrupted testing technique is invoked where the load is halted in the material instability zone, following necking but prior to fra cture. Sample microstructures in the severely necked region are microscopic ally examined in three dimensions using a serial sectioning method. The mic rographs are then stacked sequentially on a computer to reconstruct three-d imensional microstructures. Computer simulated equivalent microstructures w ith elliptical or ellipsoidal particles and cracks are constructed for enha nced efficiency; which are followed by tessellation into meshes of two- and three-dimensional Voronoi cells. Various characterization functions of geo metric parameters are generated and sensitivity analysis is conducted to ex plore the influence of morphological parameters on damage. Micro-mechanical modeling of two-dimensional micrographs are conducted with the Voronoi cel l finite element method (VCFEM). Inferrences on the initiation and propagat ion of damage are made from the two-dimensional simulations. Finally, the e ffect of size and characteristic lengths of representative material element (RME) on the extent of damage in the model systems is investigated. (C) 19 99 Acta Metallurgica Inc. Published by Elsevier, Science Ltd. All rights re served.