Precision alloy, is a special physical properties (such as magnetic, electrical, thermal and other properties) of the metal material. The vast majority of precision alloys are based on ferrous metals, and only a few are based on non-ferrous metals. (Including magnetic materials), elastomeric alloys, expansion alloys, hot bimetallic, electrical alloys, hydrogen storage alloys (see hydrogen storage materials), shape memory alloys, magnetostrictive alloys (see magnetostrictive materials), etc. The In addition, the actual application of some new alloys are also included in the scope of precision alloys, such as damping alloy, stealth alloy (see stealth material), magnetic recording alloy, superconducting alloy, microcrystalline amorphous alloy.