Alloys are made by combining at least one metallic element with other metals or nonmetal elements, especially to give greater strength or resistance to corrosion.
They are homogeneous mixtures of two or more substances.
Duralumin:
Duralumin is an alloy of 95% of Aluminium(Al), 4% of copper(Cu), 0.51% of Magnesium(Mg), 0.49% of Manganese(Mn).