Evaluation of Fatigue Strength Characteristics of Al–Mg Oxide Dispersed Aluminum Composite

Aluminum is a lightweight metal that is soft and highly malleable; thus, it offers good workability. In addition, it also exhibits corrosion resistance due to the oxide film formed on its surface. Therefore it can be adopted for various applications such as engine cylinders and, the frames and rims in a bicycle. Typically, aluminum alloys are widely used. Recently, metal matrix composites, which are composites of a base metal (such as aluminum alloys) and a reinforcing material (such as ceramics), have been employed as they are cheap and feature excellent properties that cannot be obtained via other materials. In this regard, this study aims to develop a novel composite material wherein Al–Mg oxide is dispersed in Al alloy. Fatigue tests were employed to evaluate the fatigue strength of this novel composite, and the results were compared with those of the Al/SiC composite. It was found that the Al/SiC composite material exhibited higher fatigue strength for a lower number of cycles, whereas the proposed material achieved greater fatigue strength for a higher number of cycles. Furthermore, scanning electron microscopy images of the fracture surfaces of these materials indicated that Al/SiC primarily failed due to an intergranular fracture, whereas the proposed composite failed due to a transgranular fracture. It was also observed that the fractures originated at segregated Si crystals near the surface.