Metal is a material (an element, a compound or an alloy) that is generally hard, shiny and opaque. Chemically, metals form positive ions and most have strong reactive affinity with certain non-metallic elements, thereby producing salts. Metals are good reflectors of light, have good thermal and electrical conductivity. Metals are also malleable, fusible and ductile.Metals are the basic components in alloys. The actual base metal may be silver, platinum, gold or other metals. Even with gold, silver, and platinum, they are generally mixed with other metals to increase their strength and durability.
Alloys are metals that have been mixed together. Separately, the metals are already hard and durable but when mixed together the alloy take on characteristics of the metals they are made from. Alloys offer extra durability, greater strength, and a wide spectrum of properties usually not found in a base metal.
Take iron for example, which is already a strong metal, but when mixed with carbon, steel is formed. Steel is stronger and lighter than regular iron and this has given a boost to the construction industry where now taller and bigger buildings can be constructed.
Important Features of Metals and Alloys
Strength and Hardness
The hardness of the metal or alloy is important and this affects the ability of the metal to be worked with. An example would be aluminium alloys. While some aluminium alloys are soft and easy to bend, others are hard. Hardness also affects the ability of a metal or alloy to retain its formed shape. Then the weight of the metal also affects its durability over time and the bigger a metal object gets, the more weight it has across its entire structure, thus affecting its durability.
Some metals and metal alloys have high structural strength per unit mass, thus are able to carry large loads or resist impact damage. Through specific engineering, metal alloys can be made to have high resistance to shear, torque and deformation. The strength and resilience of metals have led to their frequent use in high-rise building and bridge construction, as well as most pipes and railroad tracks.
Most metals and their alloys are vulnerable to the elements, including rain, salt water, excessive sun, or even sand and dirt. Rust and corrosion are the biggest contributors to metal failure. The ability for a metal or alloy to stand the test of time is also a very important feature to consider.
Good conductor of heat and electricity
Metals are good conductors, with the ability to carry an electric current over a distance without much loss of energy. Electrical power grids distribute electricity via metal cables whilst the in the home, electrical systems are wired with copper wire due to its good conducting properties. The thermal conductivity of metal is useful for containers to heat materials over a flame and to prevent overheating of sensitive equipment, metal is usually used for heat sinks.
The material cost is also important as typically, the more durable or long lasting a metal or alloy is, the more it costs. Metals that have a wide application with a multitude of uses are usually more in demand, which will cause the price to be higher.