In scientific terms, alloy is a mixture of two or more metals. Similarly, alloy wheels are generally a mixture of metals like aluminium, magnesium and sometimes even nickel. Even though steel itself is an alloy of iron and carbon, in the automotive industry, alloy wheel are wheel rims known to be made of nonferrous metal (nonferrous metals are metals that do not contain iron and are rust-free).
The earliest alloy wheels were made of magnesium, which often suffered deformities due to the
ductility of the metal. In recent years, aluminium has replaced magnesium as low cost and high performance alloy wheels.