Mechanical properties and fracture behavior of layered 6061/SiCp composites produced by spray atomization and co-deposition

Spray atomization and co-deposition was used to synthesize layered 6061/SiC p MMCs with different values of inter-layer spacing. The distribution of Si C particles had a constant base level of SIC particles, upon which a series of Gaussian distributions of additional SiC particles were superimposed. T he yield strength was noted to be essentially independent of the inter-laye r spacing, however, the ultimate tensile strength and elongation varied wit h the inter-layer spacing. The fractographic examinations indicated that th e higher SiC Volume fraction layers were the preferential regions for crack generation. The fracture sequence in the layers was believed to play an im portant role in the tensile behavior. The layered MMCs possessed a relative ly high fracture toughness, with a concomitant increase in the growth tough ness. The plasticity of the lower SiC volume fraction layers was thought to be the cause of the observed improvement in toughness. (C) 1998 Acta Metal lurgica Inc. Published by Elsevier Science Ltd. All rights reserved.