Damage-tolerant Titanium Alloys Are Core Materials For Advanced Fighter Jets
As the main material of aircraft components, titanium alloys need to meet the requirements of damage tolerance design. At present, the damage tolerance performance of titanium alloys is improved mainly by reducing the content of alloy interstitial elements (C, N, O, etc.) and the β treatment process (including β processing and β heat treatment). For example, β-annealed Ti-64 is used in the engine pylon of the A380 aircraft, which greatly improves fracture toughness and reduces crack growth rate compared with α+β annealing. Typical foreign titanium alloys with damage tolerance include Ti-64 ELI and Ti-6-22-22S, etc., and domestic damage tolerance titanium alloys include TC4-DT, TC21, TA15 ELI, etc. In the 1970s, the United States began to adopt the idea of damage tolerance design, and the 900MPa medium-strength damage tolerance titanium alloy Ti-64 β ELI was first applied to the horizontal stabilizer shaft on the F-16 fighter jet, which is a key safety life-class bearing. on the force component. Subsequently, damage-tolerant titanium alloys have also been applied to rotating parts such as the main rotor and tail rotor of helicopters such as the UH60A Black Hawk.
In the 1980s, in order to meet the needs of further weight reduction, the United States developed 1000MPa high-strength damage-tolerant titanium alloys such as Ti-6-22-22S, which were used in F-117 and F/A-18 E/F. Wait for the fighter. On this basis, American F-22 and F-35 and other fourth-generation fighters have applied a large number of medium-strength Ti-64 β ELI and high-strength Ti-6-22-22S damage tolerance titanium alloys to improve the aircraft. The combat performance and comprehensive life of the aircraft play a key role. In the total consumption of 38.8% titanium alloy in the F-22 aircraft, the damage-tolerant titanium alloy accounts for 80% of the total titanium alloy consumption, of which Ti-64 ELI is 73%, and Ti-6-22-22S is 7%. my country has successively developed medium-strength TC4-DT and high-strength TC21 damage-tolerant titanium alloys and their β-processing technology, which has achieved high and low strength matching, and has been applied in relevant key load-bearing components of aircraft.
The damage tolerant titanium alloy TC4-DT is widely used in new generation fighter jets. Next-generation fighter structures are designed with durability and damage tolerance in mind. In order to meet the requirements of light weight and long life, a large number of titanium alloys are used in the structure. Among them, the medium-strength damage-tolerant titanium alloy TC4-DT accounts for about half of the total titanium alloy, and is the most used titanium alloy in the whole machine. Compared with TC4, the control range of TC4-DT alloying elements is narrower, and the content of interstitial elements such as carbon, nitrogen, hydrogen, and oxygen is lower. The crack propagation resistance is greatly improved. TC21 is a high damage tolerance α+β type titanium alloy developed by our country. It has the characteristics of high strength, high toughness and low crack growth rate. It has good comprehensive performance matching and is widely used in aerospace fields, such as aircraft. Body bulkheads, load-bearing beams, engine frames and other load-bearing components with high strength requirements.
This article comes from Baidu
