CONTRIBUTIONS REGARDING THE CORROSION BEHAVIOUR OF SOME AL-CU-MG SUPERALLOYS
The paper presents a comparative study, using gravimetric method, on corrosion behaviour of some aluminum superalloys used in aeronautical field. The corrosion rate and penetration index were respectively determined by mass loss measurements, immersing the aluminum alloys (DURAL and 2090 –type alloys) with different metallurgical processing states (extruded, quenched and aged) in an aqueous NaCl 50 g/L solution. The corrosion behaviour settle of the analyzed aluminum alloys was made by framing into classification of corrosion stability and corrosion resistance degree, respectively. The study demonstrates that the quenched aluminum alloy of 2090-type has the best corrosion behaviour, with the smallest corrosion penetration index in the metallic matrix. It was evidenced that all aluminum superalloys tested on corrosion in a NaCl solution are stable or very stable on corrosion, with the degree of corrosion resistance between 2 and 5. The study also demonstrates that the gravimetric method is an efficient method for appreciation of the corrosion behaviour of aluminum superalloys, allowing a selection of the adequate metallurgical processing state for obtaining a higher corrosion resistance.