Effect of reinforcement size on low cycle fatigue behavior of SiC particle reinforced aluminum matrix composites

Abstract

From the examination of the particle size effect on the cyclic deformation in SiC/Al composites, the authors offer the following conclusions: SiCp/Al composite displayed continuous cyclic softening after initial hardening for any two or three cycles. In contrast, the unreinforced matrix showed initial cyclic hardening, cyclic stability and second hardening. Higher stress in response to a given strain amplitude were observed with the composite with fine (10 {micro}m) SiC particles in comparison with the composite with coarse (32 {micro}m) SiC particles. In addition, the evolution of cyclic softening became faster when the particle size increased. The low cycle fatigue endurance of the composites was generally lower than that of the unreinforced matrix. The decrease in particle size led to a higher fatigue resistance at lower strain amplitudes, but reduced the fatigue life at higher strain amplitudes. The particle size effect on cyclic response behavior can be explained when the difference in interparticle spacing and thus the difference in plastic deformation ability between the coarse and fine particle composites are taken into account. The particle size effect on fatigue-life behavior was explained in terms of the fracture modes.