Mechanical Properties and Fracture Behavior of Functionally graded 6061/SiCp Composites Produced by Spray Atomization and Co-Deposition

摘要

Spray atomization and co-deposition was used to synthesize functionally graded 6061/SiC_p MMCs. Each MMC was comprised of mean inter-spacing layers with graded SiC volume fraction. For an individual layer, the distribution of SiC particles had a constant base level of SiC particles, upon which a Gaussian distribution of additional SiC particles was superimposed. The yield strength was noted to be essentially independent of inter-layer spacing, however, the ultimate tensile strength and elongation varied with inter-layer spacing. The fractographic examinations indicated that the higher SiC volume fraction layers were the preferential regions for crack generation. The fracture sequence in the layers was believed to play an important role in the tensile behavior. The graded MMC possessed a relatively good fracture toughness, with a concomitant increase in the growth toughness. The plasticity of the lower SiC volume fraction layers was thought to be the cause of the observed improvement in toughness.