In the field of turbine engines, titanium alloys are widely used in various critical components due to their unique performance advantages, meeting complex and demanding operational conditions. Below is a detailed introduction to the application of titanium alloys in turbine disks, turbine blades, guide vanes, and combustion chambers, along with a discussion on the development trends and new technologies in high-temperature alloys.
1,High-Temperature Titanium Alloys for Turbine Disks
Turbine disks endure uneven thermal loads during operation, with the rim area experiencing higher temperatures than the center, resulting in significant thermal stress. Additionally, the dovetail teeth bear the highest centrifugal forces, subjecting them to complex stress conditions. Therefore, turbine disk materials must meet stringent requirements: high yield and creep strength, excellent thermal and mechanical fatigue resistance, low thermal expansion coefficient, no notch sensitivity, and superior low-cycle fatigue performance. High-temperature titanium alloys, with their exceptional properties, are an ideal choice for turbine disk materials, ensuring stable and reliable operation under high-temperature and high-stress conditions.
2, High-Temperature Titanium Alloys for Turbine Blades
Turbine blades are among the most critical components in a turbine engine. Although they operate at slightly lower temperatures than guide vanes, they endure substantial and complex forces under extremely harsh conditions. Thus, turbine blade materials must possess: high oxidation and corrosion resistance, excellent creep and rupture strength, good mechanical and thermal fatigue resistance, and balanced high- and medium-temperature performance. High-temperature titanium alloys meet these rigorous demands, ensuring reliable blade operation under extreme conditions and extending service life.
3,High-Temperature Titanium Alloys for Guide Vanes
The first-stage guide vanes are among the components most subjected to thermal shock in turbine engines. However, as stationary parts, they experience relatively low mechanical loads. In practice, issues such as stress-induced distortion, thermal cracking due to rapid temperature fluctuations, and burn damage from overheating often lead to failures. Based on their working conditions, guide vane materials must exhibit: sufficient endurance strength and thermal fatigue resistance, high oxidation and corrosion resistance, and, if cast alloys are used, good castability. High-temperature titanium alloys and related casting technologies meet these requirements, improving the reliability and lifespan of guide vanes.
4,High-Temperature Alloys for Combustion Chambers
Due to the complex structure of gas turbines, different sections experience varying temperatures and stress conditions. Combustion chambers endure relatively low mechanical stress but significant thermal stress. Key requirements for combustion chamber materials include: high-temperature oxidation and hot gas corrosion resistance, adequate short-term and long-term strength, excellent thermal fatigue resistance, good workability (endurance, bending performance), and weldability, along with long-term microstructural stability at operating temperatures. Selecting suitable high-temperature alloys ensures stable combustion chamber performance in high-temperature environments, reducing failures caused by material issues.
5,Development Trends and New Technologies in High-Temperature Alloys
To meet the demands of next-generation gas turbines for high-performance materials, advancements continue in directional solidification casting and single-crystal casting technologies. Additionally, powder metallurgy high-temperature titanium alloys and new anti-oxidation/hot-gas erosion protective coatings have seen widespread application.
6, Powder Metallurgy High-Temperature Alloy Technology
"FGH51"a powder metallurgy high-temperature alloy, is a γ-phase precipitation-strengthened nickel-based alloy prepared via powder metallurgy. The γ-phase accounts for about 5% by volume, with forming elements constituting approximately 50% in atomic fraction. The manufacturing process involves vacuum induction melting to produce master alloy ingots, followed by atomization to create pre-alloyed powder, which is then processed into component blanks. Compared to conventional cast and forged high-temperature alloys, FGH51 offers uniform microstructure, fine grains, high yield strength, and superior fatigue resistance, making it the highest-strength high-temperature alloy for 650°C applications. It is primarily used in rotating components of high-performance engines, such as turbine disks and load-bearing rings, significantly enhancing performance and reliability.
7, Advanced Coating Technologies
To increase turbine blade operating temperatures and extend service life, protective coatings-especially those resistant to hot corrosion-must meet stringent requirements. Traditional diffusion aluminide and aluminosilicide coatings can no longer satisfy the demands of high-pressure turbine blades exposed to oxidation and high-velocity hot gas erosion, limiting their use to low-pressure turbine guide vanes and struts.
