Types and uses of titanium alloys

      Titanium is an important structural metal that developed in the 1950s. Many countries in world have recognized the importance of titanium alloy materials and have successively carried out research and development, and have been put into practical application.
      The first practical titanium alloy the Ti-6Al-4V alloy developed by the United States in 1954. Because of its good heat resistance, strength, plasticity, toughness formability, weldability, corrosion resistance, and biocompatibility, it has become the ace of the titanium alloy industry. The usage of this alloy has accounted for75% to 85% of all titanium alloys. Many other titanium alloys can be regarded as its modification.
     The industrial production of titanium began in 148. In the 1950s and 1960s, the development of high-temperature titanium alloys for aircraft engines and structural titanium for the fuselage was the main focus. In the 1970s, a number of corrosion-resistant titanium alloys were developed. Since the 190s, corrosion-resistant titanium alloys and high-strength titanium alloys have been further developed. The use temperature of heat-resistant titanium alloys has been increased from 40°C in the 1950s to 600~650°C in the 1990s, which has made titanium's position in the engine shift from the cold end of the engine (fan and compressor) to the hot end of the engine (turbine). Structural titanium alloys are towards high strength, high plasticity, high strength and high toughness, high modulus, and high damage tolerance.
    Since the 1970s, shape memory such as Ti-Ni, Ti-Ni-Fe, and Ti-Ni-Nb have also appeared and have been increasingly widely used in engineering.
China began to titanium and titanium alloys in 1956 and began the industrial production of titanium materials in the mid-1960s, and the TB2 alloy was.

2. Main Classification of Titanium Alloy
    By using the different characteristics of the above two structures of titanium, adding appropriate alloy elements and gradually changing their phase transformation temperature and phase composition content, titanium alloys with different organizations can be obtained.
At room temperature, titanium alloys have three basic organizations, and alloys are divided into the following three categories: α alloys, (a β) alloys, and β alloys. China uses TA, TC, and TB to represent respectively.
α titanium alloys
    Whether at general temperature or at higher actual application temperature, it is α. The organization is stable, the wear resistance is higher than that of pure titanium, and the oxidation resistance is strong. At temperatures of 500℃ ~00℃, it still maintains its strength and creep resistance, but it cannot be strengthened by heat treatment, and the room temperature strength is not high.
β titanium
    It has high strength without heat treatment. After quenching and aging, the titanium alloy is strengthened, and the room temperature strength can reach 1372~1666MPa; but the thermal stability is poor, and it is not for use at high temperatures.
α β titanium alloys
   It is a two-phase alloy with good comprehensive performance, good organizational stability, good toughness, plasticity, high temperature.