Titanium-A armor

Titanium-A Armor is the most common and typical battle plating used by the UNSC on ships. It is composed of a high-grade Titanium-50 alloy that is usually brownish in colour. Titanium-A has numerous uses throughout the UNSC. This is due largely to titanium's properties; it is light and extremely strong; with a high tolerance for heat. It took newfound importance after the beginning of the Human-Covenant War. To contend with the Covenant's plasma weaponry, Humans needed armour that would withstand the heat of the directed plasma. This however, is usually boiled away in seconds and does not effectively dissipate the plasma either.

Its primary use is as armour for ships. UNSC Frigates have sixty centimetres of plating on their hull, and UNSC Destroyers have up to two meters of it. Supercarriers like the had 10 meters. Marines sometimes have thin Titanium-A armour suits, though these are an increasingly rare sight. These suits are slowly being replaced by ceramic variants, such as those seen on the ODSTs in Halo 3.

The UNSC uses Titanium-A for construction of bases as well, to make them less susceptible to destruction. Places such as HIGHCOM Facility Bravo-6, CASTLE Base and Camp Hathcock used Titanium-A armour in their superstructures.