High purity magnesium die casting alloys: Impact of metallurgical principles on industrial practice

All the current magnesium die casting alloys are based upon aluminium as the main alloying element. To obtain optimum corrosion performance, the chemical composition must be strictly controlled, especially with regard to the heavy elements iron, nickel and copper. In the present paper the metallurgical principles for removal of iron by addition of manganese are discussed. The mutual liquid solubilities of iron and manganese in the various alloys are investigated, and corrosion is related to the content of the two elements. Consequences for production of ingots and subsequent melting of the ingots in the die casting operation are considered. The presented information provides input for alloy standardisation.