oa Effect of Heat Treatment on the Corrosion Performance of Welded Al-6063 Alloy

A large number of aluminum alloy plates, which are mainly used as the decks, the shell plates and the cabin reinforcing plates, are used in the construction applications. Al-6063 high strength aluminum alloy and its weldment are widely utilized in such applications due to the high specific strength, good fracture toughness, low cycle fatigue properties and easy-welding properties. The main aim of this article is to determine the effect of heat treatment on the microstructure and the corrosion of welded AA6063 Al alloy at base, weld and heat affected zone. The laboratory immersion test technique were used to evaluate the effect of different environmental media, such as NaOH, NaCl, H2SO4 and H3PO4 on corrosion behavior of T4 and T6-temepered alloys. Mass loss and corrosion rate measurements were utilized as criteria for evaluating the corrosion behavior of the aged-hardened alloys. The corrosion rate was calculated for various immersion periods. The aged-hardened alloys were subjected to potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) testing. The result shows that the corrosion rate of the alloy was due to the nature of heat treatment given to the samples. It was found that the corrosion rate of the Al(6063) alloy was higher in the T4-tempered alloy compared to T6-tempered alloy. The corrosion behavior of welded alloys were differ one zone to another. The students would like to express their grateful acknowledgement for financial and in-kind support received from the Hydro Aluminum Company (HYDRO) and Qatalum Company and from Center of Advanced Materials, Qatar University.