Physical properties of titanium

Titanium has a relative density of 4.506, a melting point of 1668℃, and a boiling point of 3287℃. Its resistivity is 42 x 10⁻⁸ Ω·m (20℃). Due to its dense oxide layer, it is corrosion-resistant. At room temperature, it does not react with oxygen, halogens, or water; however, when heated to red-hot, it reacts with oxygen to form titanium dioxide. It does not react with nitric acid, dilute sulfuric acid, or alkalis, but it is soluble in concentrated sulfuric acid, hydrofluoric acid, and aqua regia.

Titanium is malleable; high-purity titanium can have an elongation of 50-60% and a reduction of area of ​​70-80%, but its strength is low, making it unsuitable as a structural material. The presence of impurities in titanium greatly affects its mechanical properties, especially interstitial impurities (oxygen, nitrogen, carbon), which can significantly increase its strength and significantly reduce its ductility. The excellent mechanical properties of titanium as a structural material are achieved through strict control of appropriate impurity content and the addition of alloying elements. Titanium is a silvery-white, malleable metal with great industrial importance due to its many valuable properties. It is less dense than iron, much stronger than aluminum, and has corrosion resistance similar to platinum.

These properties make it an ideal material for constructing engines, aircraft frames, missiles, and marine facilities, which require lightweight, high strength, and resistance to extreme temperature changes-properties in which titanium is unmatched. Some of titanium's properties, such as tensile strength, are enhanced by its ability to alloy with aluminum; furthermore, the α-β transition temperature of aluminum-titanium alloys is higher than that of pure titanium. Titanium can also form useful alloys with molybdenum, manganese, iron, and other metals.