The Effects of Individual Addition of Sn, Nd, and Ca on the Microstructure, Mechanical Properties, and Corrosion Behavior of the Mg-Li-Al Alloy

In this study, Mg-8Li-2Al, Mg-8Li-2Al-1.5Sn, Mg-8Li-2Al-1.5Nd, and Mg-8Li-2Al-1.5Ca alloys were produced by the gravity die casting method. The effects of individual addition of Sn, Nd, and Ca on the microstructure, mechanical properties, and corrosion behavior of the Mg-8Li-2Al alloy were studied. The presence of intermetallic compounds (AlLi, Mg2Sn, Al2Nd, Al11Nd3, and Al2Ca) in the alloys, which affected the mechanical properties, was identified by X-ray diffraction analysis of the experimental alloys. Hardness and tensile tests were performed to determine the mechanical properties of the alloys. According to the hardness measurements, the addition of alloying elements increased the hardness of the alloys. The measurement of the tensile and compression tests shows that the best outcomes were achieved at Mg-8Li-2Al-1.5Sn alloy, compared to Mg-8Li-2Al alloy, with an increase of 18.3% in tensile stress and 34% in compression stress. Also, the tensile elongation value of Mg-8Li-2Al-1.5Sn alloy was measured as 10.4%, which was higher than the Mg-8Li-2Al-1.5Nd and Mg-8Li-2Al-1.5Ca alloys. Electrochemical corrosion test results showed that Mg-8Li-2Al-1.5Sn alloy had the lowest corrosion rate of 10.49 mpy, which is thought to be due to the formation of protective Mg2Sn phases.