Pure titanium is a silver white metal with many excellent properties.The density of titanium is 4.54g/cm3, which is 43% lighter than steel and slightly heavier than the famous light metal magnesium.The mechanical strength is almost the same as that of steel, which is two times larger than that of aluminum and five times larger than that of magnesium. Titanium is resistant to high temperature. Its melting point is 1942k, which is nearly 1000K higher than gold and 500K higher than steel.
Titanium belongs to the metal with active chemical properties. When heated, it can react with non-metal elements such as O2, N2, H2, s and halogen. However, at room temperature, titanium surface is easy to form a very thin and dense oxide protective film, which can resist the action of strong acid or even aqua regia, showing strong corrosion resistance.As a result, metals in acid, alkali and salt solutions become porous while titanium remains intact. Liquid titanium can dissolve almost all metals, so it can form alloys with many metals. Titanium steel made by adding titanium into steel is tough and elastic.Titanium and metals such as Al, Sb, be, Cr, Fe form interstitial compounds or intermetallic compounds.
Airplanes made of titanium alloy carry more than 100 passengers more than those made of other metals. The submarine can resist both seawater corrosion and deep pressure. Its submergence depth is 80% higher than that of stainless steel submarine. At the same time, titanium is non-magnetic and will not be found by mines, which has a good anti monitoring effect.
Titanium has the property of "biological affinity". In the human body, it can resist the corrosion of secretions and is non-toxic. It is suitable for any sterilization method. Therefore, it is widely used in the manufacture of medical devices, such as artificial hip joint, knee joint, shoulder joint, hypochondriac joint, skull, active heart flap and bone clamp.When new muscle fiber rings are wrapped around these "titanium bones", these titanium bones start to maintain normal human activity. Titanium is widely distributed in human body. The content of titanium in normal human body is less than 15mg per 70kg body weight, and its effect is not clear.However, it has been proved that titanium can stimulate phagocytes and enhance immunity.
Titanium and titanium alloy are very important lightweight structural materials, which have very important application value and broad application prospect in aerospace, aviation, vehicle engineering, biomedical engineering and other fields