Abstract
Effect of the volume fraction on the fatigue strength was studied for three commercially fabricated aluminum matrix composites containing SiC whiskers (SiCw) and SiC particles (SiCp). The fatigue strength of SiCw/A2024 composite increased with the increase of the volume fraction of SiC whiskers, while the fatigue strength of SiCp/A356 composite showed maximum at a volume fraction of 10%. The fractography revealed that the fatigue crack would initiate at many voids situated near the specimen surface (fish eye failure) for 20%-SiCp/A356. It is suggested that the fatigue strength decreases due to the fish eye failure for 20%-SiCp/A356 composite. It is pointed out that the fish eye failure would prevent to improve the fatigue strength for SiC particulate reinforced aluminum composites.
