Magnesium alloys have been considered due to its high strength to weight ratio. In this study, cubic samples of as-cast AZ91 were cut in the dimension of 1  1  1 cm3, and then a hot severe plastic deformation process was applied on them at 350 C. The samples were continuously compressed in the direction of x, y and z. The raw samples and one, two and three-directional forged samples were evaluated by Vickers hardness, potentiodynamic polarization, scanning electron microscopy (SEM), and electrochemical impedance methods. Vickers hardness evaluation showed that by applying forging in three continual directions, the hardness of the raw sample increased from 74 HV to 86 HV. However, by increasing the number of forging pass, the corrosion current density decreased from 2 mA/cm2 to about 6.9 10-4 mA/cm2. SEM evaluation indicated that corrosion zones were reduced by increasing deformation. Polarization resistance obtained from electrochemical impedance method increased from 381.99 to 1914.4 .cm2 related to the as-cast and three-directional deformed samples, respectively. The event confirmed that anodic regions reduced on the surface of forged samples. The mentioned results confirmed the positive effect of grain size reduction, applied compressive strength and blocking of the presented micro-voids on the corrosion behavior of the alloy. تفاصيل المقالة