Mechanical and corrosion properties of Mg–MgO and Mg–Al2O3 composites fabricated by equal channel angular extrusion method

Abstract

Equal channel angular extrusion (ECAE) has shown great potential for the consolidation of powdered materials. In the present article, the mechanical and corrosion properties of Mg–MgO and Mg–Al₂O₃ composites produced by the ECAE method were studied. Pure magnesium reinforced with 0, 10, 20, and 30 ​vol percentages of MgO and Al₂O₃ particles were hot consolidated at 600 ​MPa in an ECAE die without prior cold compaction or canning of the powders. Results indicated that the reinforcement content is directly proportional to the hardness, compressive strength, and corrosion resistance of the fabricated composites, while it has an inverse relationship with the relative density. The lowest relative density and the highest corrosion rate were obtained for the Mg+30%MgO composite samples, as opposed to the pure magnesium with the highest relative density and the lowest corrosion rate. Besides, composites reinforced with 30 and 20 ​vol percentages of alumina revealed the highest hardness and the highest compressive strength, which were 55% and 74% higher than that of the pure magnesium sample, respectively. Based on SEM and EDX analyses, it was shown that Mg–Al₂O₃ samples had finer grain sizes compared to Mg–MgO composites.