Properties and processing of magnesium-tin-calcium alloys

The development of new creep resistant magnesium alloys has become a major issue in recent years and therefore further alloy development is necessary. Newly developed alloys are based on the binary system Mg-Sn. Sn as major alloying element was chosen due to its high solid solubility over a wide temperature range and due to the possible formation of Mg₂Sn intermetallic precipitates with a high melting temperature of about 770°C. These characteristics suggest that a fairly large volume fraction of thermally stable Mg₂Sn particles can be formed during solidification. This makes it possible that the Mg-Sn alloys can be developed as creep resistant magnesium alloys and/or wrought magnesium alloys. Previous investigations indicate that the Mg-Sn alloys have a comparable or even better creep properties than AE42 alloy. This paper presents an overview about recent works on the developments of Mg-Sn alloys performed in MagIC, Helmholtz-Zentrum Geesthacht, which includes: microstructural characterization, creep deformation and hot deformation, and corrosion behaviour. Very positive results have been obtained and show Mg-Sn-Ca alloy systems can be developed for power train and hand tool applications.