Titanium& Alloys

Commercially Pure Grade 2 titanium is by a VERY wide margin, the most readily available and least expensive of titanium and it's alloys. Grade 2, commonly referred to as CP2, is not much stronger than aircraft alloy aluminum.  CP2's greatest strength is in it's corrosion resistance. In many atmospheres, it's essentially inert.

The second most common grade is 6AL-4V, also known as 6-4 or Grade 5 titanium. By alloying titanium with aluminum and vanadium, the resulting alloy and it's properties are quite amazing. While most alloys lose their tensile strength at high temperatures, 6-4 maintains that strength from cryogenic all the way through extremely elevated temps. 

There are many other alloys of titanium available in the market however CP2 and 6-4 cover 96% of the market on a tonnage basis.

IMPORTANT NOTE TO ENGINEERS: Be careful not to specify other less common grades of titanium to a new print unless the demand will be very high (>10K Lbs/ year) and allow 24-36 months for delivery.