magnesium alloys, Cast alloys and wrought alloys
Magnesium alloys (Elektron, Magnox, and Magnuminium) are mixtures of magnesium with other metals (called an alloy), often aluminum, zinc, manganese, silicon, copper, rare earths and zirconium. Magnesium is the lightest structural metal. Magnesium alloys have a hexagonal lattice structure, which affects the fundamental properties of these alloys. Plastic deformation of the hexagonal lattice is more complicated than in cubic latticed metals like aluminum, copper and steel. Therefore magnesium alloys are typically used as cast alloys, but research of wrought alloys has been more extensive since 2003. Cast magnesium alloys are used for many components of modern cars, and magnesium block engines have been used in some high-performance vehicles; die-cast magnesium is also used for camera bodies and components in lenses.
Practically all the commercial magnesium alloys manufactured in the United States contain aluminum (3 to 13 per cent) and manganese (0.1 to 0.4 per cent). Many also contain zinc (0.5 to 3 per cent) and some are hard enable by heat treatment. All the alloys may be used for more than one product form, but alloys AZ63 and AZ92 are most used for sand castings, AZ91 for die castings, and AZ92 generally employed for permanent mold castings (while AZ63 and A10 are sometimes also used in the latter application as well). For forgings, AZ61 is most used, and here alloy M1 is employed where low strength is required and AZ80 for highest strength. For extrusions, a wide range of shapes, bars, and tubes are made from M1 alloy where low strength suffices or where welding to M1 castings is planned. Alloys AZ31, AZ61, and AZ80 are employed for extrusions in the order named, where increase in strength justifies their increased relative costs.
Magnesium casting proof stress is typically 75-200 MPa, tensile strength 135-285 MPa and elongation 2-10%. Typical density is 1.8 g/cm3 and Young's modulus is 42 GPa. Most common cast alloys are: AZ63, AZ81, AZ91, AM50, AM60, ZK51, ZK61, ZE41, ZC63, HK31, HZ32, QE22, QH21, WE54, WE43, and Electron 21.
Magnesium wrought alloy proof stress is typically 160-240 MPa, tensile strength is 180-440 MPa and elongation is 7-40%. The most common wrought alloys are: AZ31, AZ61, AZ80, Electron 675, ZK60, M1A, HK31, HM21, ZE41, and ZC71.