Temperature and Particle Size Influence on the High Cycle Fatigue Behavior of the SiC Reinforced 2124 Aluminum Alloy

In this work the high cycle fatigue behavior of a particulate reinforced 2124 aluminum alloy, manufactured by powder metallurgy, is investigated. SiC particles with a size of 3 mu m and 300 nm and a volume fraction of 5 and 25 vol %, respectively, were used as reinforcement component. The present study is focused on the fatigue strength and the influence of particle size and temperature. Systematic work is done by comparing the unreinforced alloy and the reinforced conditions. All of the material conditions are characterized by electron microscopy and tensile and fatigue testing at room temperature and at 180 degrees C. With an increase in temperature the tensile and the fatigue strength decrease, regardless of particle size and volume fraction due to the lower matrix strength. The combination of 25 vol % SiC particle fraction with 3 mu m size proved to be most suitable to achieve a major fatigue performance at room temperature and at 180 degrees C. The fatigue strength is increased by 40% when compared to the unreinforced alloy, as it is assumed the interparticle spacing for this condition reaches a critical value then.