The world's first successfully developed high-temperature titanium alloy is Ti-6Al-4V, with a usage temperature of 300-350 ℃. Subsequently, alloys such as IMI550 and BT3-1 were developed with temperatures up to 400 ℃, as well as alloys such as IMI679, IMI685, Ti-6246, and Ti-6242 with temperatures ranging from 450 to 500 ℃. The new high-temperature titanium alloys that have been successfully applied in aircraft engines include IMI829 and IMI834 alloys from the UK; Ti-1100 alloy from the United States; Russian BT18Y, BT36 alloys, etc. In recent years, foreign countries have adopted rapid solidification/powder metallurgy technology, fiber or particle reinforced composite materials to develop titanium alloys as the development direction of high-temperature titanium alloys, which can increase the service temperature of titanium alloys to over 650 ℃. McDonnell Douglas has successfully developed a high-purity, high-density titanium alloy using rapid solidification/powder metallurgy technology. Its strength at 760 ℃ is equivalent to that of titanium alloys currently used at room temperature.

Titanium alloys based on titanium aluminum compounds

Compared with general titanium alloys, titanium aluminum compounds as sodium based Ti3Al (α 2) and TiAl (γ) intermetallic compounds have the advantages of good high-temperature performance (operating temperatures of 816 and 982 ℃ respectively), strong oxidation resistance, good creep resistance, and light weight (density only 1/2 of nickel based high-temperature alloys). These advantages make them a competitive material for future aviation engines and aircraft structural components. At present, two Ti3Al based titanium alloys Ti-21Nb-14Al and Ti-24Al-14Nb - # v-0.5Mo have started mass production in the United States. Other Ti3Al based titanium alloys developed in recent years include Ti-24Al-11Nb, Ti25Al-17Nb-1Mo, and Ti-25Al-10Nb-3V-1Mo. The composition range of TiAl (γ) based titanium alloys of interest is TAl - (1-10) M (at.%), where M is at least one element of v, Cr, Mn, Nb, Mn, Mo, and W. Recently, TiAl3 based titanium alloys have attracted attention, such as Ti-65Al-10Ni alloy.

High strength and toughness beta titanium alloy

The earliest beta titanium alloy was B120VCA alloy (Ti-13v-11Cr-3Al) developed by American company Crucible in the mid-1950s. β - type titanium alloy has good cold and hot processing properties, is easy to forge, can be rolled and welded, and can achieve high mechanical properties, good environmental resistance, and a good combination of strength and fracture toughness through solid solution aging treatment. The representative types of new high-strength and high toughness β - type titanium alloys are as follows: Ti1023 (Ti-10v-2Fe - # al), which has excellent forging performance comparable to the commonly used high-strength structural steel 30CrMnSiA in aircraft structural components; Ti153 (Ti-15V-3Cr-3Al-3Sn), this alloy has better cold working performance than industrial pure titanium, and its room temperature tensile strength after aging can reach over 1000MPa; β 21S (Ti-15Mo-3Al-2.7Nb-0.2Si) is a new type of anti-oxidation and ultra-high strength titanium alloy developed by the Timet division of the American titanium metal company. It has good anti-oxidation performance, excellent cold and hot processing performance, and can be made into foil with a thickness of 0.064mm; The SP-700 (Ti-4.5Al-3V-2Mo-2Fe) titanium alloy developed by Japan Steel Pipe Company (NKK) has high strength, a superplastic elongation rate of up to 2000%, and a superplastic forming temperature 140 ℃ lower than Ti-6Al-4V. It can replace Ti-6Al-4V alloy in manufacturing various aerospace components using superplastic forming diffusion bonding (SPF/DB) technology; The BT-22 (TI-5v-5Mo-1Cr-5Al) developed by Russia has a tensile strength of over 1105MPA.

Flame retardant titanium alloy

Conventional titanium alloys have a tendency to burn alkanes under specific conditions, which greatly limits their application. In response to this situation, various countries have conducted research on flame-retardant titanium alloys and achieved certain breakthroughs. Alloy c (also known as T with a nominal composition of 50Ti-35v-15Cr (mass fraction)) developed by the Qiang country is a flame retardant titanium alloy that is insensitive to continuous combustion and has been used in F119 engines. BTT-1 and BTT-3 are flame-retardant titanium alloys developed in Russia, both of which are Ti Cu Al series alloys with excellent thermal deformation performance, and can be used to make complex parts.

Medical titanium alloy

Titanium is non-toxic, lightweight, high-strength, and has excellent biocompatibility, making it an ideal medical metal material that can be used as an implant for human body. At present, Ti-6Al-4v ELI alloy is still widely used in the medical field. But the latter can precipitate extremely small amounts of vanadium and aluminum ions, reducing their cellular adaptability and potentially causing harm to the human body, which has long attracted widespread attention in the medical community. The United States began developing aluminum free, vanadium free, and biocompatible titanium alloys as early as the mid-1980s for use in orthodontics. Japan, the United Kingdom, and others have also done a lot of research in this area and made some new progress. For example, Japan has developed a series of alpha+beta titanium alloys with excellent biocompatibility, including Ti-15Zr-4Nb-4ta-0.2Pd, Ti-15Zr-4Nb-aTa-0.2Pd-0.20-0.05N, Ti-15Sn-4Nb-2Ta-0.2Pd, and Ti-15Sn-4nb-2Ta-0.2Pd-0.20. These alloys have better corrosion strength, fatigue strength, and corrosion resistance than Ti-6Al-4v ELI. Compared with alpha+beta titanium alloys, beta titanium alloys have higher strength, better incision performance, and toughness, making them more suitable for implantation in the human body. In the United States, five types of beta titanium alloys have been recommended for the medical field, namely TMZFTM (TI-12Mo - ^ Zr-2Fe), Ti-13Nb-13Zr, Timetal 21SRx (TI-15Mo-2.5Nb-0.2Si), Tiadyne 1610 (Ti-16Nb-9.5Hf), and Ti-15Mo. It is estimated that in the near future, such titanium alloys with high strength, low elastic modulus, excellent formability and corrosion resistance are likely to replace the widely used Ti-6Al-4V ELI alloy in the medical field.