Titanium is the main constituent in titanium alloys, of course, but they can contain a significant amount of other elements, which are added for a variety of metallurgical reasons. The strength of titanium alloys can often be comparable to steel, but they have the advantage of having only about 60% of the weight. The lower density of titanium allows these alloys to be used in applications where lower weight is advantageous.
Like iron, pure titanium has two solid crystalline forms. At low temperatures, the crystalline phase is called alpha, and it has a hexagonal closed packed (HCP) structure. At high temperatures, the solid phase is called beta and has a body centered cubic (BCC) structure. The temperature at which the solid becomes fully beta is called the beta-transus temperature. With the additions of alloying elements to titanium, the beta-transus temperature can vary from about 1250°F to about 1925°F, depending on the specific composition of the alloy.