This paper investigates the role of alloying elements of Ti and Al on the evolution of the morphology, hardness variation, and corrosion resistance of Mg-xAl-yTi alloy ( x = 3, 6, and 9 wt.% and y = 0.2, 0.4, and 0.6 wt.%). The microstructure of the alloys consisted of α -Mg and β -Mg 17 Al 12 phases. As the Al content increased, the area fraction of the α / β eutectic increased. The maximum area fraction of the α / β eutectic was seen in Mg-9Al-0.2Ti alloy. In contrast, as the Ti content increased, the area fraction of the α / β eutectic decreased and it became discontinuous. In the Mg-3Al-0.2Ti alloy, the minimum hardness of 96.32 ± 2.56 HV was obtained, while, in Mg-9Al-0.6Ti alloy, the maximum hardness of 147.68 ± 5.75 HV was obtained. The hardness values indicated that the addition of the Ti and Al alloying elements increased the alloys’ hardness, mainly because of the refined grain structure. According to corrosion testing results, the corrosion resistance decreased as the Al content increased. In contrast, as the Ti content increased, the corrosion potential increased and the current density declined. Observation of the corrosion surfaces showed that the continuous corroded regions in the Mg-9Al-0.2Ti alloy were replaced with discontinuous corroded regions with shallower pits, indicating the enhanced corrosion resistance as a result of increasing Ti content.
Li et al. (Thu,) studied this question.