Homogeneous Mixtures (a.k.a. solutions)

A substitution alloy is a type of alloy in which atoms of one metal replace atoms of another metal within the crystal structure. This typically occurs when the metals involved have similar atomic sizes and crystal structures. A common example is brass, where copper atoms are partially substituted by zinc atoms. The substitution results in modified properties, such as enhanced strength or corrosion resistance, depending on the combination of metals.

An interstitial alloy is a type of alloy where smaller atoms, typically nonmetals like carbon, fit into the spaces (interstices) between the larger metal atoms in the crystal lattice. These smaller atoms do not replace the metal atoms but occupy the gaps, leading to changes in the properties of the metal, often making it harder and stronger.

A classic example of an interstitial alloy is steel, where carbon atoms fit into the gaps between iron atoms, significantly increasing its hardness and tensile strength compared to pure iron.