Agradecimentos: The authors acknowledge the financial support provided by IFPA—Federal Institute of Education, Science and Technology of Pará, UFPA—Federal University of Pará, and CNPq—The Brazilian Research Council (Grants 302846/2017-4, 400634/2016-3, and 301600/2015-5), CAPES—Coordination of Superior Level Staff Improvement, Brazil, and FAPESP (São Paulo Research Foundation, Brazil: Grant 2017/16058-9) Ver menos

In the present experimental investigation, Al-3wt%Cu and Al-3wt%Cu-0.5wt%Mg alloys castings are produced by a horizontal solidification technique with a view to examining the interrelationship among growth rate (G(R)), cooling rate (C-R), secondary dendrite arm spacing ((2)), Vickers microhardness (HV), and corrosion behavior in a 0.5M NaCl solution. The intermetallic phases of the as-solidified microstructures, that is, -Al2Cu, S-Al2CuMg, and -Al7Cu2Fe, are subjected to a comprehensive characterization by using calculations provided by computational thermodynamics software, optical microscopy, and scanning electron microscopy/energy-dispersive spectroscopy. Moreover, electrochemical impedance spectroscopy and potentiodynamic polarization tests have been applied to analyze the corrosion performance of samples of both alloys castings. Hall-Petch-type equations are proposed to represent the HV dependence on (2). It is shown that the addition of Mg to the Al-Cu alloy has led to a considerable increase in HV; however, the Al-Cu binary alloy is shown to have lower corrosion current density (i(corr)) as well as higher polarization resistance as compared to the corresponding results of the Al-Cu-Mg ternary alloy Ver menos