Investigation of microstructural and mechanical properties of AM50 magnesium alloy with addition Ce on die casting

Inside of engineering materials used in industry, interest for magnesium alloys has been increasing in automotive and aviation sectors due to lightness and less harmful gas emissions effects by reduced car weight. In this study, AM50 magnesium alloy, which is from Mg-Al-Mn family and widely used in industry, has been used and in different amounts (wt. 0.5 % and wt.1 %) cerium (Ce) was added to this alloy. Obtained alloys was cast under 680 °C temperature and different shot sleeve speed (3 m/s, 4 m/s, ve 5 m/s) conditions in high pressure die casting machine. The effects of Ce addition and different shot sleeve speeds on microstructure, mechanical properties and corrosion behaviour have been investigated. Microstructural characterisation was carried out by optical microscope (OM), scanning electron microscope (SEM) and XRD. Mechanical properties have been determined by hardness, tension and compression tests. Corrosion behaviour has been evaluated by test results of hydrogen evolotion, weight loss and electrochemical polarisation. Moreover, computer aided die casting simulation&analysis has been done and compared with theoretical calculations. 5 m/s shot sleeve speed is induced the highest mechanical properties in high pressure die casting of AM50 magnesium alloy. By increasing shot sleeve speed, mechanical properties were enhanced. In addition, grain size was decreased and new Al11Ce3 phase formed due to addition of Ce to AM50 magnesium alloy. New phase and reducing in grain size led to high temperature strenght of AM50 magnesium alloy. Al11Ce3 phase decreased Mg17Al12 phase amounts in microstructure, thus corrosion rate was reduced. When wt.1% Ce added to AM50 magnesium alloy and cast under 5 m/s shot sleeve speed, higher mechanical properties and improved corrosion resistance was achieved in high pressure die casting. Computer aided die casting simulation&analysis and theoretical calculation results and experimental findings have been in good agreement.