An alloy is a uniform mixture. It is usually produced by melting the mixture of ingredients. It is made up of two or more chemical elements, of which at least one is a metal. It is a combination of a metal with at least one other metal or nonmetal.
An alloy has properties different from the metals it is made of. The components of alloys cannot be separated using a physical means. Alloying elements can be added to metal to increase the number of properties including hardness, strength, corrosion resistance, machinability, and much more. Most alloys are made by melting the metals, mixing them while they are liquid to form a solution, then leaving them to cool and turn solid again.
Combining a pure metal with one or more other metals or non-metals often makes it better. For example, steel is an alloy made from iron but it is stronger than iron.
The first alloy to be discovered was Bronze. Bronze is made from copper and tin. Bronze was discovered a very long time ago in the prehistoric period. Then, bronze was being used for making tools and weapons. This period was known as the Bronze Age.
The melting point is the temperature at which a solid change to a liquid. Most alloys do not have a single melting point. The temperature at which melting just starts is called solidus and the temperature at which the melting is just finished is called liquidus.
Some common alloys
There are some common alloys: Examples of alloys include stainless steel, brass, bronze, white gold, 14k gold, and sterling silver.
- Brass is hard and durable, making it suitable for plumbing fixtures and machined parts. It is made of 35% zinc and 65% copper and is used for musical instruments, jewelry, faucets, and decorative hardware.
- Stainless steel is mostly iron, plus more than 11% chromium, and various amounts of nickel and carbon and is used for tableware, cookware, and surgical tools. It typically contains chromium, nickel, and other elements to resist rust or corrosion.
- Steel is made of 99% iron and 1% carbon and is used for tools, car bodies, machinery, girders, and rails. The other elements add a desired quality to the steel, such as hardness or tensile strength.
- Bronze is made of mostly copper and some tin and is used for boat hardware, screws, and grillwork.
- Alnico is a mix of aluminum, nickel, and cobalt, and it is used to make permanent magnets.
- Lead is a metal alloying element that is used to improve machinability.