Structural and mechanical study on Mg–xLM (x = 0–5 wt.%, LM = Sn, Ga) alloys

Abstract

Abstract Low-melting point metals, such as Sn and Ga, can improve both the mechanical and corrosion properties of pure Mg. Currently, Mg–Sn based alloys are being considered for high-temperature applications, and both Mg–Sn and Mg–Ga based alloys are also being considered as possible candidates for biodegradable materials. Although these binary systems have already been the subject of research, only limited information on their characteristics has been published. Therefore, as-cast Mg–Sn and Mg–Ga alloys containing 1, 3.5 and 5 wt.% of alloying elements were studied in the present work. Moreover, the effect of extrusion on Mg–Sn and Mg–Ga alloys containing 3.5 wt.% of the alloying element was studied. Structural and chemical analyses of the alloys were performed by using light and scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. The mechanical properties were determined by Vickers hardness measurements and tensile and compressive testing. The as-cast alloys were characterized by a dendritic morphology with the presence of secondary eutectic phases. Both Sn and Ga exhibited hardening and strengthening effects on magnesium. The extruded alloys were characterized by fine-grained microstructures with a grain size of approximately 3 and 6 μm for Mg-3.5Sn and Mg-3.5Ga alloys, respectively, and significantly improved mechanical properties compared with the as-cast state. The ultimate tensile strength reached almost 250 MPa for both extruded alloys compared with 120–150 MPa for the as-cast condition. The results indicate that Mg–Sn- and Mg–Ga-based alloys appear to be suitable candidates for both engineering and medical applications.