Magnesium alloys

The material. Magnesium is a metal almost indistinguishable from alumi­num in color but of lower density. It is the lightest of the light-metal trio (with partners aluminum and titanium), and light it is: a computer case made from magnesium is barely two thirds as heavy as one made from alu­minum. Titanium, aluminum, and magnesium are the mainstays of air­frame engineering. Only beryllium is lighter, but its expense and potential toxicity limit its use to special applications only. Magnesium is flammable, but this is only a problem when it is in the form of powder or very thin sheet. It costs more than aluminum but nothing like as much as titanium.

Composition

Mg + alloying elements, e. g., Al, Mn, Si, Zn, Cu, Li, rare earth elements. General properties

Density Price

Mechanical properties

Young’s modulus Yield strength (elastic limit)

Tensile strength Elongation Hardness—Vickers Fatigue strength at 107 cycles Fracture toughness

Thermal properties

Melting point

Maximum service temperature Thermal conductor or insulator?

Thermal conductivity Specific heat capacity Thermal expansion coefficient

Electrical properties

Electrical conductor or insulator?

Electrical resistivity

Magnesium, the lightest of the light alloys, is increasingly used for components of cars and other vehicles.

Ecoproperties: processing

Casting energy Casting CO2 footprint Deformation processing energy Deformation processing CO2 footprint

Typical uses. Aerospace; automotive; sports goods such as bicycles; nuclear fuel cans; vibration damping and shielding of machine tools; engine case castings; crank cases; transmission housings; automotive wheels; ladders; housings for electronic equipment, particularly mobile phone and portable computer chassis; camera bodies; office equipment; marine hardware and lawnmowers.