Titanium is a Class IVB element of the periodic table. It looks like steel and has a melting point of 1,672 °C. It is a refractory metal. Titanium is abundant in the earth’s crust, much higher than common metals such as Cu, Zn, Sn and Pb. China’s titanium resources are extremely rich. In the large-scale vanadium-titanium magnetite discovered in the Panzhihua area of Sichuan, the associated titanium metal reserves amount to about 420 million tons, which is close to the sum of foreign proven titanium reserves.
Pure titanium has strong mechanical properties, good plasticity and easy processing. If there are impurities, especially O, N, C increase the strength and hardness of titanium, but it will reduce its plasticity and increase brittleness.
Titanium is a metal that is easily passivated, and in an oxygen-containing environment, its passivation film can heal itself after being damaged. Therefore, the dry corrosive medium is stable. Titanium and titanium alloys have excellent corrosion resistance and can only be eroded by hydrofluoric acid concentrations. Especially stable, after the titanium or titanium alloy is removed, it is still as bright as ever, far superior to stainless steel.
Another important property of titanium is its low density. Its strength is 3.5 times that of stainless steel and 1.3 times that of aluminum alloy, which is the highest among all industrial metal materials.
Liquid titanium dissolves almost all metals to form various alloys such as solid solutions or metal compounds. The addition of alloying elements such as Al, V, Zr, Sn, Si, Mo and Mn can improve the properties of titanium to meet the needs of different sectors. For example, Ti-Al-Sn alloy has high thermal stability and can work for a long time at a relatively high temperature; superplastic alloy represented by Ti-Al-V alloy can be elongated by 50% to 150%. Processed, its maximum elongation can reach 2 000%. The elongation of the plastic working of the general alloy is not more than 30% at the maximum.
Due to the above excellent properties, titanium enjoys the reputation of “future metal”. Titanium alloys have been widely used in various sectors of the national economy. They are indispensable materials for rockets, missiles and space shuttles. Titanium alloys are used in large quantities in ships, chemicals, electronic devices and communication equipment, as well as in several light industry sectors, but titanium is more expensive and limits its widespread use.