Abstract
In addition to copper, aluminum and some precious metals, magnesium and its alloys offer respectable thermal and electrical conductivity with high specific properties. Alloys based on the Mg-Zn-Ca system also have the added advantage of being suitable as a bone replacement material due to its high biocompatibility. This research examines various Mg-Zn-Ca alloys for their use as bone replacement materials as well as conductors for next generation transportation. Mg-Zn-Ca alloys were cast using a permanent mold and their respective microhardness, corrosion resistance and castability was assessed. The microstructure was also characterised using optical and electron microscopy. Higher Zn and Ca content alloys had higher microhardness (60 HV) but a lower electrical conductivity (30 %IACS). However, low or high Zn/Ca ratio alloys had better castability and high resistance to corrosion as compared to alloys with a moderate Zn/Ca ratio. When the Mg-Zn-Ca alloys were produced with high cooling rates, the resulting finer microstructure had well distributed Mg-Zn-Ca intermetallic phases that resulted in hard, corrosion resistant alloys.