An Investigation of the Influence of Nano-Cobalt Oxide on Microstructure and Mechanical Properties of 7075 Aluminium Alloy

Abstract

Aluminium Alloy AA7075 is the strongest heat-treatable aluminium series. For that they have suitable properties and tremendous applications, especially in the aviation and aerospace industries. The effect of a minor Nanocobalt oxide on the microstructures and mechanical properties of AA7075 was investigated in this work.The investigation was carried out as a cast AA7075 with 0.2, 0.4, 0.6 and 0.8% Nano-cobalt. The optical microscopy demonstrates that the grain size of alloys was decreased with the increasing of Nano -cobalt oxide content. The Scanning electron microscopy and EDX show that the cobalt oxide present between the grains at the grain boundary. Moreover, there are Al-Zn-Mg, Al-Fe-Cu, Si-Al-Zn, Al-Fe-Cu-Co-Zn, and Al-o-Si-Zn-Cu compounds.The mechanical properties examination shows that the hardness decreased and yield stress, increased with an increasing in the Nano-cobalt content. The ultimate tensile stress and modulus elasticity also increased with the increase of Nanocobalt content, except alloy with 0.8% Nano-cobalt which decreased to 5.87 GPA.

Impact, Hardness and Fracture Morphology of Aluminium Alloy (Al-Si) filled Cobalt Oxide Nanoparticles at Various Stir Casting Temperatures

“…One reinforcement type that can be used for aluminium alloys is cobalt oxides (CoO) nanoparticles. Increasing loading of CoO nanoparticles has increased the yield stress, ultimate tensile stress, and modulus of elasticity of produced metal composites [5]. But the relationship between the filler added to the melting temperature of Al/Si alloys during the stir casting process is still not being understood.…”