Question

What is an alloy? Explain the differences in structure between substitutional and interstitial alloys. Give an example of each type.

Short answer

An alloy is a mixture of different metals and elements. It has several metallic properties and can be classified as substitutional alloy and interstitial alloy.

The difference between substitutional and interstitial alloys are that substitutional atoms contains nearly same sized metal atoms whereas interstitial alloys contain both large and small sized atoms of different elements. The former one follows atom exchange mechanism while the later one follows interstitial mechanism

Examples of some substitutional alloys are brass, pewter, plumber’s solder etc. Examples of some interstitial alloys are e.g., carbon steels etc.

Step-by-step solution

Definition of alloy

An alloy is a mixture of different metals and elements. It has several metallic properties and can be classified as substitutional alloy and interstitial alloy.

Substitutional alloy, are formed when some the host metal atoms are substituted by other metal atoms which are of similar size. In an interstitial alloy smaller atoms are inserted in some of the interstices (holes) in the closest packed metal structure.

Difference

The difference between substitutional and interstitial alloys are that substitutional atoms contains nearly same sized metal atoms whereas interstitial alloys contain both large and small sized atoms of different elements. The former one follows atom exchange mechanism while the later one follows interstitial mechanism

Examples of some substitutional alloys are brass, pewter, plumber’s solder etc. Examples of some interstitial alloys are e.g., carbon steels etc.