ENHANCED CORROSION RESISTANCE ANDMECHANICALINTEGRITY OF AL6061/BERYL METAL COMPOSITES: ANELECTROCHEMICAL STUDY IN ACIDICCHLORIDEANDALKALINE MEDIA
Al6061 aluminium alloy has been widely used in aerospace, automotive, and marine industries for its lowdensity, excellent mechanical properties, and medium corrosion resistance. Nevertheless, its structural reliability is still limited by the susceptibility to localised corrosion in severe environments. In the present investigation, beryl (Be3Al2Si6O18), a natural beryllium aluminium cyclosilicate, is utilised as a reinforcement phase to enhancecorrosion resistance and mechanical properties of Al6061 alloy. In order to make the aluminium/boron balideMMCs more homogeneous and have better interface bonding, these stir-cast MMCs with 2, 4 and 6 wt%of beryl were successfully extruded. The mechanical properties, such as hardness, density and porosity, were initiallydetermined, then the corrosion behaviour was explored electrochemically in 0.5 M HCl and 0.1 MNaOHsolutionsby means of Tafel extrapolation and EIS methods. The microstructure and phase characteristics were systematicallyinvestigated using a scanning electron microscope (SEM) and an X-ray diffractometer (XRD). Results showedthat the composite with 6 wt% beryl had the smallest current density and maximum LIN, described by a higher resistance to polarisation, which proved an improved stability of the passive film. These results indicate that theincorporation of beryl reinforcement via CEP effectively enhances not only the corrosion resistance but alsothestructural property of Al6061 alloy, and thus its potential for use in corrosive, aggressive, and high-simultaneousproperty engineering conditions.
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