Studying on the fatigue behavior of Al- Al2O3 metal matrix nano composites processed through powder metallurgy

Excellent mechanical properties and fatigue performance of Al/Al2O3 metal-based nanocomposites caused to introduce this material as a good candidate for various applications. In this regard, the preparation and characterization of this composite can be considered as a hot issue for research. The study was carried out in several steps including: (i) preparation of Al/Al2O3 metal-based nanocomposites at various Al2O3 content as reinforcement (4, 6 and 8 wt.%) using wet attrition milling; (ii) hot forward extrusion process of prepared samples; (iii) determination of mechanical properties of prepared composite by tensile test; (iv) usage of rotating-bending fatigue test for determination of the fatigue performance of prepared composite and (v) analysis of the fracture surfaces of fatigue tests specimens to determine the mechanism/s of failure based on scanning electron microscope analysis. The results showed that the presence of Al2O3 nanoparticles up to 6 wt.% enhanced the fatigue strength of Al/Al2O3 nanocomposites while the higher amount of reinforcement has a detrimental effect on the fatigue strength. Also, the statistical nature of fatigue data confirmed the higher coherency as well as homogeneity of prepared composites by 6 wt.% of reinforcement. The EDX spectrum confirmed the presence of Al2O3 at the origin of crack. As a consequence, the most probable mechanisms for crack initiation through the cyclic loading can be considered as the fracture and/or detachment of reinforcement particles.