Multi-scale characterization of spatially heterogeneous systems: implications for discontinuously reinforced metal-matrix composite microstructures

A new multi-scale technique is presented For characterizing the spatial dis tribution of second-phase particles in two-dimensional distributed multi-ph ase systems. The implications for the characterization of reinforcement dis tributions in discontinuously reinforced metallic matrix composite microstr uctures are discussed, along with results of the analysis both for simulate d and experimental discontinuously reinforced aluminum (DRA) materials. A s ystematic variation in the degree of spatial heterogeneity is observed with increasing length scale. This result leads to the definition of the parame ter L-H or homogeneous length scale. The relevance of L-H measured for a re al DRA microstructure is then discussed in the context of statistical varia tions in mechanical propel ties such as tensile strength, ductility, and fr acture toughness. (C) 2001 Published by Elsevier Science B.V.