Nowadays most primary magnesium is used for metallurgical purposes. We talk about them a lot of times yet. They are - magnesium-based alloy castings and wrought products, alloying additions to aluminum and other metals, for desulphurization of iron and steel, as a reducing agent to produce metals from their oxides and chlorides and in anodes for cathodic protection and so on.
Magnesium-based alloy castings and wrought products make up about 20% of free-market magnesium shipments. The latest scientific research on the use of magnesium alloys and their corrosion protection are depicted in the Latest Technical Developments.
Magnesium in its pure form is soft, mechanically weak, and hence not generally used for structural and special applications. As with other metallic alloy systems, a combination of well-known hardening mechanisms (solid solution hardening, particle dispersion hardening, work hardening, and grain boundary hardening) determines the mechanical properties of magnesium alloys. The correct combinations between different chemical elements give us other properties like reactivity of the melt, cast-ability, and corrosion performance. That is enough for magnesium popularity in metallurgy.
The alloying elements used with magnesium can be put in two major categories.
1) Elements that actively influence the melt. Examples are: beryllium (<= 15 p pm), which lowers the rate of melt oxidation, and manganese (<= 0.6 wt%), which reduces the iron content and hence the corrosion rate of the alloys. These additions are active in relatively small amounts and do not require extensive solubility in the melt.
2) Elements that modify the microstructure of the alloy via the above-mentioned hardening mechanisms. This group includes elements that influence cast-ability. Except for grain-refining additions (carbon inoculation), which can be active in small amounts, these elements must be relatively soluble in liquid magnesium.