Papers by Keyword: Mg-Al

Abstract: AZ31 Mg / 5083 Al clad sheet was fabricated by the hot rolling method and its mechanical properties were investigated in this study. The tensile strength and yield strength of Mg- Al clad samples were slightly higher than that of AZ31 Mg sample, resulting in high strength 5083 Al alloy. Also, in the case of the AZ31 Mg sample, tensile strength indicated different values to the rolling directions. The thickness of interface layers between magnesium and aluminum materials increased with increasing rolling temperature. The thickness of interface layer was about 1.2 μm and 1.6 μm, respectively. The difference of thickness on the interface layer with variation of rolling temperature was attributed to promote the diffusion between magnesium and aluminum materials. The Vickers hardness of Mg-Al interface layer was around 125 Hv. The interface layer composed of hard inter-metallic phases which may act a increment of Vickers hardness depending upon its thickness.

Abstract: Ceramic coatings were synthesized on pure Mg and binary Mg-7.1wt%Al alloy by plasma electrolytic oxidation (PEO) technique, and the effect of current ratio, C2/C1, ranging from 0.2 to 0.85 on their mechanical and electrochemical properties was investigated. As the C2/C1 ratio increased, the thickness of the coating layer increased, while surface roughness was almost unchanged. The hardness and wear resistance had a marked tendency to increase with increasing C2/C1 ratio and Mg-Al alloy showed higher hardness and wear resistance at all C2/C1 ratios compared to pure Mg. The weight loss of the pure Mg and Mg-Al alloy in 3.5%NaCl solution was reduced by coatings. However, it had no dependence on the C2/C1 ratio. The wear resistance of the coated Mg-Al alloy was better than that of the coated pure Mg.

Abstract: The range of applications for magnesium alloys is still limited due to their relatively poor corrosion behavior. In recent years, various new magnesium alloys were developed, some of them with improved corrosion properties, thus opening new fields of application. However, the number of alloying elements for the use in conventional cast processes is limited due to their interaction with liquid magnesium, other alloying elements or large differences in the melting temperatures. The possibilities for grain refinement by post-processing are also restricted. PVD techniques can help to produce supersaturated precipitation free and microcrystalline magnesium layers. Using ion beam and magnetron sputtering, binary or ternary Mg-Al, Mg-Ti and Mg-Sn alloy systems as well as standard alloys (AM50, AZ91 and AE42) were deposited on silicon and on magnesium substrates. The effect of the microstructure on the corrosion properties was studied by comparing as cast material and PVD coatings using potentiodynamic polarization, linear polarization resistance, and electrochemical impedance techniques.

Abstract: Ceramic coatings were synthesized on pure magnesium, binary Mg-Al and Mg-Zn alloys by plasma electrolytic oxidation (PEO) technique, and their mechanical and electrochemical properties were investigated. The coatings showed porous microstructure and some volcano top-like pores on the surface. The coatings on Mg-Al alloys consisted of MgO, MgAl2O4 and Al2O3. In the coatings on Mg-Zn alloys, MgO and ZnO were detected. The hardness and wear resistance showed slight dependence on Al content but no tendency to increase with increasing Zn content. The coated Mg alloys with Al, Zn showed better corrosion resistance in 3.5%NaCl solution but poor corrosion resistance in methyl alcohol, compared to the coated pure Mg.