The research and development of high-temperature titanium alloy rose in the 1950s. At first, Ti-6AI-4V was developed in the United States in 1954, which can be applied to the working environment of 350 ℃ with good comprehensive properties. As an excellent aerospace material, it has started the research upsurge of titanium alloy.
The R & D process of high-temperature titanium alloy can be divided into three periods according to strengthening method and phase composition:
(1) From 1950 to 1970, the service temperature of high-temperature titanium alloy exceeded from 350 ℃ to 480 ℃. During this period, its understanding was that disordered solid solution strengthening phase group became a+ β Phase.
(2) The intermediate period was 1970 ~ 1976. During this period, the creep resistance of high-temperature titanium alloy was enhanced due to the wide application of a small amount of Si, and the service temperature of the alloy exceeded from 480 ℃ to 540 ℃. Although the alloy is still mainly strengthened by solid solution, due to the addition of a small amount of Si, the alloy phase group becomes a+ β Phase and a small amount of silicide.
(3) The third period is from 1977 to 1984. The main sign of this period is that phase (TA1) is used as a reinforcing phase, so the service temperature of high-temperature titanium alloy has exceeded from 540 ℃ to 600 ℃. It is difficult to meet the service requirements of 600 ℃ only by solid solution strengthening. However, when a certain amount of phase A and silicide are precipitated in the alloy, the creep resistance and durability of the alloy can be enhanced, so as to meet the service requirements at 600 ℃
The rapid development of the aviation industry has promoted the research and development of high-temperature titanium alloy. The United States, Britain, Russia, and other developed countries in this field have created their own superalloy titanium alloy system.
In the early stage of development, Ti-6AI-4V developed by the United States is a very classic superalloy, which is an (a + b) two-phase type. It has the advantages of good high-temperature strength, thermal stability, and hot workability. It is a milestone in the development history of superalloy titanium alloys and also lays a foundation for the research of titanium alloys in many countries.
Subsequently, in the 1960s, the United States made a breakthrough and introduced t-62468 and ti-6242 to increase the service temperature from 350 ℃ to 450 ℃. Its main feature is the addition of B stable element Mo, which improves the properties of these alloys compared with Ti-6AI-4V, especially the creep resistance.
In the 1970s, the United States succeeded again and developed the improved t-6242s of T-6242, raising the service temperature to 540 ℃. Its main feature is the addition of Si, which improves the creep resistance and thermal stability of the alloy.
In 1988, t-1100 alloy was introduced in the United States, which is ti-a1-sn-zr-mo-si, near a titanium alloy with a service temperature of 600 ℃. Ti-1100 alloy is successfully developed by adjusting the content of alloying elements with reference to ti-6242s. Due to its excellent comprehensive properties, mature Ti-1100 alloy is widely studied as a sample high-temperature titanium alloy, and it is applied to the parts of the t552-712 modified engine.
