The ignition proof of Mg-Gd-Y-Zn-Zr magnesium alloy have restricted their use in many applications, such as civilian aircraft and other aerospace components. Recent research activities have aimed at increasing the resistance of Mg alloys to oxidation and ignition by modifying the MgO surface scale to a more protective barrier oxide between the metal and the gas environment. Alloying is one of the techniques to alter the surface oxide structure. In this thesis, three different alloying elements, namely a rare earth element Yttrium (Y), Gadolinium (Gd) and post-transition metal Zinc (Zn), are studied over a range of different compositions with respect to their effects of Heat treatment and effect of Extrusion on Ignition temperature and oxidation layer of magnesium alloys.
Mg-Gd-Y-Zn-Zr magnesium alloys was optimized for high ignition proof property, which did not burn in the air at 936? C up to 30min. the oxidation behavior of the alloy was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), at 673K,773K, and 873K and SEM analysis indicated that dense and compact oxide film composed of MgO, YO and GdO, ZnO formed. The oxidation behavior was characterized by the selective oxidation and the EDS results implied that the Y-rich areas were preferred paths for selective oxidation.
Keywords: Magnesium alloys, Ignition-Proof, Heat treatment, Extrusion, Oxidation behavior.