How alloy design changes warship armor

Can the different kinds of alloy be explained more clearly?

Added elements can fill gaps in a metal's structure, replace some of its existing constituents, or do both, allowing different balances of strength and flexibility.

The explanation begins with a regular arrangement of a metal's constituents. In an interstitial alloy, added material occupies gaps in that arrangement. In a substitutional alloy, it replaces some of the existing constituents. The diagrams connect these different arrangements to changes in strength and flexibility, with combinations used to seek both properties. Armor needs to absorb and disperse impact energy without breaking, so hardness alone is an incomplete design objective.