High-Temperature Titanium Alloys and Various Types of Titanium Alloys: Classification and Properties

High-Temperature Titanium Alloys

The world's first high-temperature titanium alloy successfully developed was Ti-6Al-4V, with a service temperature of 300-350°C. Subsequently, alloys with a service temperature of up to 400°C, such as IMI550 and BT3-1, were developed, followed by alloys like IMI679, IMI685, Ti-6246, and Ti-6242, which can operate at 450-500°C. Recently, new high-temperature titanium alloys such as the UK's IMI829 and IMI834, the USA's Ti-1100, and Russia's BT18Y and BT36 have been successfully applied in aircraft engines. In recent years, international research has focused on developing high-temperature titanium alloys using rapid solidification/powder metallurgy techniques and fiber or particle reinforced composites, aiming to increase the operating temperature of titanium alloys to above 650°C. McDonnell Douglas in the USA successfully developed a high-purity, high-density titanium alloy using rapid solidification/powder metallurgy technology, which retains its strength at 760°C, comparable to current titanium alloys at room temperature.

Titanium Alloys Based on Titanium-Aluminum Compounds

Compared to conventional titanium alloys, titanium alloys based on titanium-aluminum compounds such as Ti3Al (α2) and TiAl (γ) have advantages including excellent high-temperature performance (service temperatures of 816°C and 982°C, respectively), strong oxidation resistance, good creep resistance, and low weight (density is only half that of nickel-based superalloys). These advantages make them competitive materials for future aerospace engines and aircraft structural components. Currently, two Ti3Al-based titanium alloys, Ti-21Nb-14Al and Ti-24Al-14Nb-#v-0.5Mo, are being produced in bulk in the USA. Other recently developed Ti3Al-based titanium alloys include Ti-24Al-11Nb, Ti-25Al-17Nb-1Mo, and Ti-25Al-10Nb-3V-1Mo. The focus for TiAl (γ)-based titanium alloys is on compositions in the range of TAl-(1-10)M (at.%), where M represents at least one element from V, Cr, Mn, Nb, Mn, Mo, and W. Recently, TiAl3-based titanium alloys, such as Ti-65Al-10Ni, have begun to attract attention.

High-Strength, High-Toughness β-Type Titanium Alloys

The earliest β-type titanium alloy was B120VCA (Ti-13V-11Cr-3Al), developed by Crucible Company in the USA in the mid-1950s. β-type titanium alloys have good hot and cold workability, are easy to forge, roll, and weld, and can achieve high mechanical properties and good environmental resistance through solution-aging treatment, with an excellent combination of strength and fracture toughness. Representative new high-strength, high-toughness β-type titanium alloys include:

Ti1023 (Ti-10V-2Fe-#Al): Comparable to the commonly used high-strength structural steel 30CrMnSiA in aircraft structural components, with excellent forging properties.

Ti153 (Ti-15V-3Cr-3Al-3Sn): Has better cold workability than commercially pure titanium, with room temperature tensile strength exceeding 1000 MPa after aging.

β21S (Ti-15Mo-3Al-2.7Nb-0.2Si): Developed by the Timet division of the Titanium Metals Corporation in the USA, this new ultra-high-strength titanium alloy has excellent oxidation resistance, outstanding hot and cold workability, and can be made into foils as thin as 0.064 mm.

SP-700 (Ti-4.5Al-3V-2Mo-2Fe): Developed by NKK in Japan, this alloy has high strength and superplastic elongation of up to 2000%, with a superplastic forming temperature 140°C lower than Ti-6Al-4V, making it a potential replacement for Ti-6Al-4V in superplastic forming-diffusion bonding (SPF/DB) technology for various aerospace components.

BT-22 (Ti-5V-5Mo-1Cr-5Al): Developed in Russia, with a tensile strength exceeding 1105 MPa.

Flame-Resistant Titanium Alloys

Conventional titanium alloys have a tendency to combust under specific conditions, which significantly limits their applications. To address this issue, various countries have conducted research on flame-resistant titanium alloys and achieved certain breakthroughs. Alloy C, also known as Ti-50V-35Cr-15Cr (mass fraction), is a flame-resistant titanium alloy developed in China that is insensitive to sustained burning and is used in the F119 engine. BTT-1 and BTT-3 are flame-resistant titanium alloys developed in Russia, both Ti-Cu-Al based, with excellent hot deformation processing performance, making them suitable for manufacturing complex parts.

Medical Titanium Alloys

Titanium is non-toxic, lightweight, strong, and has excellent biocompatibility, making it an ideal material for medical applications such as implants. Currently, the widely used alloy in the medical field is still Ti-6Al-4V ELI, but it can release trace amounts of vanadium and aluminum ions, reducing its cell compatibility and potentially causing harm to the human body. This issue has long been a concern in the medical community. The USA started developing aluminum-free, vanadium-free, biocompatible titanium alloys for orthopedic surgery in the mid-1980s. Japan, the UK, and other countries have also conducted extensive research and made some new advancements. For example, Japan has developed a series of α+β titanium alloys with excellent biocompatibility, including Ti-15Zr-4Nb-4Ta-0.2Pd, Ti-15Zr-4Nb-4Ta-0.2Pd-0.20~0.05N, Ti-15Sn-4Nb-2Ta-0.2Pd, and Ti-15Sn-4Nb-2Ta-0.2Pd-0.20, which have superior corrosion strength, fatigue strength, and corrosion resistance compared to Ti-6Al-4V ELI. Compared to α+β titanium alloys, β titanium alloys have higher strength, better notch performance, and toughness, making them more suitable for implants. In the USA, five β titanium alloys have been recommended for medical applications: 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, these high-strength, low-elastic-modulus, and excellent-formability and corrosion-resistant β titanium alloys are likely to replace the widely used Ti-6Al-4V ELI alloy in the medical field.

Established in 2007, Baoji Yesheng Titanium Industry Co., Ltd. is a high-tech company that integrates the production, processing, and sales of titanium and titanium alloys, nickel, zirconium, and other non-ferrous elements. It is situated in China's "Titanium Valley"-Baoji. Plates, bars, wires, tubes, standard components, forgings, equipment, and titanium and titanium alloys are the primary products. Nickel, zirconium, and alloys are also important.Welcome your consultation.