What is an Alloy

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An alloy is a substance which is formed when two or more metals are combined. They can also be formed when metals are combined with other elements. However, the properties which alloys exhibit are different than the individual properties of these elements. When you compare it to the pure metals, alloys are stronger and harder. Alloy examples include red gold which is made by combining gold and copper together. Another example of alloy includes white gold which is an amalgamation of silver and gold. Today, we will learn about what is an alloy in chemistry, alloy definition and constituents of alloy.

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Alloy Definition Chemistry

Let us now learn what alloy means in chemistry. 

An alloy refers to a combination of two or more metals, or a metal combined with one or more elements. The resulting alloy has different properties than the original elements altogether, like increased strength and hardness. For example, when elemental iron is combined with non-metallic silicon or carbon, it yields steel or silicone steel. 

Constituents of Alloy

Now that you have learned about what is the meaning of alloy, let us look at what are the constituents of alloy. An alloy consists of two or more elements, either as a compound or a solution. The components of alloys are generally metals. However, carbon is an exception to being a non-metal and an important constituent of steel. Alloys are usually produced when the mixture of its constituents is melted.

Properties of Alloy

When you have learnt about what is meant by alloy, learning the properties of alloy becomes easier.

An alloy is a substance that has metallic properties and is composed of two or more elements, out of which at least one is a metal. A metal, having metallic properties, is a material, which, when freshly made, fractured, or polished, demonstrates a lustrous appearance. It also conducts heat and electricity as well. 

Metals are generally malleable, which means that they can be easily hammered into thin sheets. They are also ductile, meaning that they can be drawn into wires as well. A metal can either be a chemical element like iron, or an alloy like stainless steel. Most of the pure metals are either very brittle, soft, chemically reactive to be practically used. When different ratios of metals are combined as alloys, it modifies the original properties of metals to give desirable characteristics. Alloys are generally made to keep them less brittle, corrosion-resistant, harder, or even have a more desirable lustre and colour.

Alloy Examples

Let us now look at some of the alloy examples.

  1. Steel

Steel is an alloy of carbon and iron. It is a popular alloy because of its low cost and higher tensile strength. However, many different types of steels consist of different amounts of carbon along with several other elements like manganese, phosphorus, sulfur, chromium, copper, nickel, and molybdenum. Primarily, the composition of iron is accounted for by iron, which is at least 75% of the total alloy’s weight. It also consists of different amounts of carbon and many other elements depending on the type of steel. Since steel has higher tensile strength and affordability, it is used in the infrastructure and construction of buildings, bodies of vehicles and electrical appliances.

  1. Bronze

Bronze is known to be an alloy of tin and copper. It is commonly used in heavy tools and gears, coins, medals, trophies and even in different forms of electrical hardware. The strength of bronze varies depending on the alloys that are used in the alloying. You must know that bronze is much superior compared to pure copper when it comes to hardness. It is also more ductile and machineable compared to pure copper.

  1. Nichrome

Nichrome is an alloy of chromium and nickel. However, it also common for the nichrome alloys to consist of iron and other similar elements. Nichrome is primarily used in resistance wires. It also has its application in several electrical appliances like bread toasters and space heaters. Nichrome alloys are also used in dental fillings.

FAQ (Frequently Asked Questions)

1. What do you mean by Alloy?

Ans. An alloy is an amalgamation of a metal or metals and other elements. Several metals or elements can be added to the existing metal for enhancing their properties. For example, pure aluminium and pure copper are relatively softer metals. However, when copper and aluminium are alloyed together, the resulting alloy has greater strength than the metals in their original states. This way, alloys add or enhance specific properties like strength, lustre or colour to the existing parent metals. 

The two or more elements to be alloyed are mixed together in their molten state. This mixture is then allowed to solidify in a sand mould or a metal. The resultant alloy is stronger and more practically useful than the pure elements or metals due to their properties.

2. How are Alloys formed?

Ans. An alloy of a metal is formed when it is combined with one or more elements. The most common and one of the oldest methods to alloy a metal is carried out by heating the metal beyond its melting point. The solutes are then dissolved into the molten liquid. This is possible even when the melting point of the solutes is much greater than that of the metal. For example, titanium in its liquid state is quite a strong solvent that is capable to dissolve most elements and metals. Also, it readily absorbs gases such as oxygen and burns in nitrogen presence. This, in turn, increases the chances of contamination from surfaces, and hence must be melted in special copper crucibles that are water-cooled and have vacuum induction-heating capacity.