Final answer:
An alloy is a homogeneous mixture of two or more elements, at least one being a metal, forming a single substance with improved metallic properties like hardness or rust resistance.
Step-by-step explanation:
An alloy is a homogeneous mixture of two or more elements, where at least one of the elements is a metal. The mixture is so intimately combined at the atomic level that it behaves as a single substance with metallic properties. For instance, steel is an alloy composed chiefly of iron with added elements such as carbon for hardness, manganese for strength, and chromium for rust resistance.
There are two main types of alloys: substitutional alloys, where atoms of different elements replace each other in the crystal structure, and interstitial alloys, where smaller atoms fit between larger ones in the crystal structure. Alloys like brass (copper and zinc) and bronze (copper and tin) exhibit superior properties compared to their constituent pure metals, which is why they are widely used in manufacturing.