Effect of Addition of Sn on High-Temperature Tensile Strength of Rare-Earth Free Mg-1Ca Alloy

Abstract

Magnesium alloys have spurred a strong interest in automobile and aerospace industries owing to their high specific strength and stiffness, with magnesium being the lightest structural metal. Alloying with rare earth improves tensile properties considerably. However, the availability of rare-earth elements is a concern. Therefore, attempts are being made to prepare alloys without rare-earth elements. One Mg-1Ca alloy was prepared with different amounts of Sn to study the impact on the high-temperature strength after dynamic recrystallization by hot rolling. Optical and electron microscopy analyzed the change in the microstructure. XRD and EDS were used to identify phases and composition of different microconstituent particles and high-temperature strength was measured at 250°C, 300°C, and 350 °C under 2 x 10-4 s -1 strain rate and at 3000C, 3500C, 4000C, and 4500C temperature under 5 x 10 -4 s -1 strain rate. According to XRD investigation, the alloys essentially comprise the Ca-containing phase and Mg2Sn particles. The Mg-1Ca-1Sn alloy exhibited maximum high-temperature strength at 250°C, attributed to the maximum amounts of MgCaSn particles. It was also found that dynamic recrystallization was accelerated by particle-stimulated nucleation and maximum refinement was found at 1% Sn-containing alloys.