Chemistry – Metals - Alloys and their properties | e-Consult

Pure metals typically have a regular, repeating crystal structure. This structure allows the metal atoms to slide past each other relatively easily when a force is applied, resulting in ductility and malleability.

When alloying, different sized atoms are introduced into the metal's crystal lattice. These foreign atoms disrupt the regular arrangement. This disruption creates stress points within the crystal structure.

These stress points impede the movement of the metal's crystal layers. The different sized atoms effectively act as obstacles, making it more difficult for the layers to slide past each other.

This increased resistance to movement is what makes alloys harder and stronger than the pure metals. The ability of the crystal structure to resist deformation is increased. The more disruption to the lattice, the harder and stronger the alloy will generally be. This is because more energy is required to overcome the obstacles and initiate plastic deformation.