Materials - Terms

Abrasive

A natural or artificial materials such as sandstone,emery, aluminium oxide or silicon carbide.



Acid

A chemical added to oil or fuel to increase it's effectiveness and obtain desirable qualities.



Adhesives

Materials or compositions that enable two surfaces to join together. An adhesive is not necessarily a glue which is considered to be a sticky substance since many adhesives are not sticky.



Aggregate

Small particles such as powderes that are used for powder metallurgy, that are loosely combined to form a whole also sand and rock as used in concrete.


Allotropic metals

Metals which exist in one lattice form over a range of temperature but at a certain temperature the lattice form changes to another type which is stable over another temperature range.



Alloy

A substance having metallic properties and is composed of two or more chemical elements, of which at least one is metal.



Alloy steel

Steel containing significant quantities of alloying elements (other than carbon and the commonly accepted amounts of manganese , silicon, sulphur and phosphorous) added to effect changes in mechanical and physical properties.