Observation of Microstructural Refinement in Mg-3Sn-2Ca Magnesium Alloy Containing Minor Sr

摘要

The microstructures of the Mg-3Sn-2Ca magnesium alloys with and without adding minor Sr were investigated and compared. The results indicate that adding 0.1 wt.% Sr to the Mg-3Sn-2Ca alloy can effectively refine the primary CaMgSn phases and grains. In addition, in the alloy containing minor Sr the volume fraction of the primary and eutectic CaMgSn phases appears to be decreased, whereas the volume fraction of the Mg2Ca precipitates seems to be increased. The mechanism for the microstructural change in the alloy containing minor Sr is possibly related to the effects of Sr additions on the onset crystallizing temperature and undercooling degree.