Fatigue Properties of a 5083/SiCp Metal Matrix Composite

摘要

Fatigue properties of SiC particles reinforced 5083 (5083/SiCp), which specifically developed for improving forgeability, were investigated on smooth specimens by rotating bending test. 5083 reinforced by 10 percent volume fraction of SiC particles exhibits fatigue strength of 95 MPa at 10~7 cycles and this value is less than that of the unreinforced 5083 by 25 MPa. However, when increasing the volume fraction of SiC particles to 15 percent, high cycle fatigue strength is almost equal and low cycle fatigue strength (from 10~5 cycles to 5 X 10~5 cycles) is apparently superior to those of the unreinforced 5083. By analyzing the observation results of fatigue crack, it is revealed that fatigue crack initiation resistance was deteriorated on the surface hut crack propagation was suppressed in the hulk of the specimen, particularly in low cycle fatigue. The cause of this fatigue crack behavior was attributed to the clustering structure of reinforcement (SiCp cluster) mechanically formed by the forging process.