Why People Use Alloys Instead of Pure Metals

People use metallic products in daily lives. There is a fact that most of the metallic products are not made from pure metals. People usually use alloys instead of pure metals due to alloys' better properties.

What are alloys? They are mixtures of at least two or more different elements. At least one of these elements must be metal. For example, steel is a mixture of iron and carbon, and bronze is a mixture of copper and tin. In alloys, there are two essential parts: main metal and alloying agent. The main metal can also be called as parent metal or base metal, and it usually occupies 90% of the mixture. Also, the alloying agent can be either metal or nonmetal. Most alloys are solid solutions, and some of them are chemically bonded.

Alloys have two different structures: interstitial and substitution. The structures of alloys are decided by the size of element. If the elements of alloying agent are smaller than the elements of parent metal, these elements can slip in between the elements of main metal, and then the metal will become interstitial alloy. If the elements of alloying agent replace some of the elements of parent metal, the substitution alloy forms.

How do alloys work? They are mixtures of at least two elements; therefore, besides main metals' properties, alloys' properties can be influenced by elements added in the parent metal. For example, steel is harder than iron. Iron atoms can slip over other iron atoms, because metallic bonds can hold metals together. However, if carbon atoms are added to iron, the iron atom will not be able to slip easily, so it becomes harder than pure iron. Steel can be used for construction because pure iron is soft and can be easily broken.

How to make alloys? There are three ways to make alloys. The first way is melting the components of alloys and mix them together, and then a solid solution will form after the mixture cools down. This is a traditional way to make alloys. The second way to make alloys is named powder metallurgy. It makes all the components into powders and then mix them together. After mixing them, the mixture will be put in a high pressure and high temperature condition to make alloys. The third way is called ion implantation, which is used to make computer chips or electronic circuits. Beams of ions will be fired into the surface layer of the main metal to make alloys.

Consequently, people tend to use alloys instead of pure metals because alloys have more and better properties than their parent metals. Also, alloys can be used for different areas, such as medicine, architecture, art and military.

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