Magnesium alloys are mixtures of magnesium (the lightest structural metal) with other metals (called alloys), usually aluminum, zinc, manganese, silicon, copper, rare earths, and zirconium. Magnesium alloys have a hexagonal lattice structure, which affects the basic properties of these alloys. Plastic deformation of the hexagonal lattice is more complex than that of cubic lattice metals such as aluminum, copper, and steel; therefore, magnesium alloys are often used as casting alloys.
Aluminum is very stable, inexpensive, and due to its sturdiness, does not bend easily under pressure. Magnesium alloys have a short solidification time. Magnesium is less stable, very expensive, and bends easily under pressure due to its softness.
Like aluminum, magnesium alloys are used in the casting of automotive parts and provide their unique mechanical and physical properties. While experiments have been carried out to replace aluminum with magnesium, it is still softer, less stable, more expensive, and bends more easily under pressure.
Although aluminum alloys take longer to solidify than magnesium alloys, their alloys provide longer mold life. Also, aluminum doesn’t require as much finishing work as magnesium. When determining the application of magnesium castings, special treatments and coatings are required.