Question

what are alloys why are they called as mixtures

Answer 1

An alloy is a mixture of metals or a mixture of a metal and another element. Alloys are defined by a metallic bonding character.[1] An alloy may be a solid solution of metal elements (a single phase) or a mixture of metallic phases (two or more solutions). Intermetallic compounds are alloys with a defined stoichiometry and crystal structure. Zintl phases are also sometimes considered alloys depending on bond types

Answer 2

Alloy can be prepared by mixing of two metal or more metal with non metal. As in alloys​ no fixed proportion of elements,So they form mixture.