A metallic mixture two or more elements. An alloy can be formed from a mixture of two of more metals e.g. copper and tin to form bronze, or by a mixture of a metallic and non-metallic element e.g. iron and carbon to form steel, or cast iron.
It has been suggested that the term alloy should only be used when there is a suggestion that the mixing was deliberate. In the study of ancient metallurgy it is difficult to prove deliberate mixing in some cases, e.g. when the ‘alloy’ could have arisen by co-smelting e.g. Cu-As and Fe-C-P alloys. So, an alternative use of the term would be – any metallic mixture of elements whose physical, mechanical, or metallurgical properties differed substantially from the constituent elements.