Classification of non-ferrous metals and titanium alloys

Titanium alloys are alloys composed of titanium based on the addition of other elements. Titanium has two kinds of homogeneous heterocrystals; titanium is a homosolar isomer, melting point of 1720 ° C in less than 882 ° C was a dense row of hexagonal crystal lattice structure, known as a titanium; in the 882 ° C above the body-centered cubic lattice structure, known as the B titanium, the use of titanium's different characteristics of the above two structures, add the appropriate alloying elements, so that the phase transition temperature and the content of the phase fraction is gradually changed to obtain a titanium alloy with different organizations.

Titanium alloy elements can be divided into three categories according to their influence on the phase transition temperature: ① stabilize a phase, improve the phase transition temperature of the elements for a stabilizing elements, aluminum, magnesium, oxygen and nitrogen, etc.. Aluminum is the main alloying element of titanium alloy, which has obvious effects on improving the strength of the alloy at room temperature and high temperature, reducing specific gravity and increasing elasticity. ② The element that stabilizes the B phase and reduces the phase transition temperature is the B stabilizing element. And can be divided into homocrystalline and eutectic type two, the former has molybdenum, niobium, vanadium, etc.: the latter has chromium, manganese, copper, silicon, etc.. The elements that have little effect on the phase transition temperature are neutral elements, such as zirconium and tin.

a titanium alloy

It is a single-phase alloy composed of a-phase solid melt, whether at the general temperature or at higher temperatures of practical applications, are a-phase, stable organization, wear resistance is higher than pure titanium, oxidation resistance, in the temperature of 500 ° C ~ 600 ° C, still maintains its strength and creep resistance, but can not be strengthened by heat treatment, room temperature strength is not high.

B titanium alloy

It is a single-phase alloy composed of B-phase solid melt, with high strength without heat treatment, and the alloy is further strengthened after quenching and aging, and the room-temperature strength can reach 1,372~1,666MPa; however, it has poor thermal stability, and it is not suitable to be used at high temperatures.

a + B titanium alloy

It is a dual-phase alloy with good overall performance, good organizational stability, good toughness, plasticity and high-temperature deformation properties can be better for hot pressure processing, quenching, aging to make the alloy strengthened. The strength after heat treatment is about 50%~100% higher than the annealed state; high-temperature strength, can work for a long time under the temperature of 400°C~500°C. The thermal stability is second to that of the a-alloy. Its thermal stability is second to a titanium alloy.

The three titanium alloys most commonly used are a titanium alloy and a + B titanium alloy; a titanium alloy cut and processed parts is the best, a + B titanium alloy is second, B titanium alloy is the worst. a titanium alloy code for TA, B titanium alloy code for TB, a + B titanium alloy code for TC.

Titanium alloys can be divided into heat-resistant alloys, high-strength alloys, corrosion-resistant alloys (titanium - molybdenum, titanium - palladium alloys, etc.), low-temperature alloys, and special function alloys (titanium - iron hydrogen storage materials and titanium - nickel memory alloys) and so on according to the use.