Influence of artificial aging on the electrochemical properties of the aluminium AA 6063 alloy

Abstract

The influence of artificial ageing on the corrosion behaviour of the aluminium alloy AA 6063 in chloride-containing solutions was studied to determine the correlation between aging parameters and corrosion through the electrochemical parameters. The present study showed that LM and standard SEM imaging with EDS observation does not expose significant differences for the artificially aged aluminium. Nevertheless, a special statistical technique with observation of the larger area showed a significant increase of the smallest precipitates which are the initial sites for the corrosion. With electrochemical measurements, we corroborated that increase of corrosion rate is directly connected to the number of precipitates and not with the total area of exposed precipitates. Scanning electron microscopy observations combined with EDS measurements were used also to establish the type of precipitates in the studied alloy. Keywords: aluminium, artificial aging, SEM, electrochemical measurements Raziskovali smo vpliv umetnega staranja na korozijske lastnosti aluminijeve zlitine AA 6063 z namenom ugotoviti soodvisnost med staranjem in elektrokemijskimi parametri. V raziskavi smo dokazali, da zgolj standardni pregled s svetlobnim in vrsti~nim elektronskim mikroskopom v kombinaciji z EDS-analizo na prvi pogled ne poka`e bistvenih razlik med razli~no toplotno obdelanimi vzorci. Ugotovili smo, da s pomo~jo preiskave na ve~jem podro~ju in s statisti~no obdelavo lahko odkrijemo povezave predvsem med manj{imi izlo~ki in elektrokemijskimi parametri. S korozijskimi meritvami smo tudi potrdili, da je pove~anje korozijske hitrosti direktno povezano s {tevilom majhnih izlo~kov in ne s se{tevkom povr{ine vseh izlo~kov. S SEM-analizo v kombinaciji z EDS-analizo smo uporabili za dolo~itev vrst vklju~kov v preiskovani zlitini.