Titanium alloys have the advantages of good corrosion resistance, non magnetism, and high specific strength, which have quickly attracted the attention of the aviation sector and have been widely used. In the 1950s, the United States applied titanium alloy bolts to B-52 bombers, achieving good weight reduction results. Titanium alloy materials have attracted the attention of aviation industry departments in various countries. Practice has proven that aviation fasteners made of titanium alloy materials can significantly reduce the weight of aircraft. For example, the Boeing 747 uses titanium alloy fasteners to reduce its weight by 1814kg. Titanium alloy materials have good positive potential performance, which can effectively prevent galvanic corrosion. At the same time, titanium alloys have good high-temperature resistance, elasticity, and non magnetism, making them widely used in the aviation industry.

1. Application of titanium alloy rivet fasteners in the aviation industry

For rivets in the aviation industry, the cold plasticity of their materials is very important and is a prerequisite for cold riveting installation. Titanium alloy rivets are usually used in areas with high corrosion resistance and low strength requirements, β Type A has excellent cold working performance and is a superior material for aviation rivet manufacturing, which can meet various requirements.

1.1 Ti-45Nb alloy

The elongation of TI-45Nb can reach over 20%, and it has good plasticity and cold working performance. Its shear and tensile strength are better than pure titanium, and the cold deformation resistance is lower than pure titanium. It is the best material choice for composite material connection rivets. In the aviation industry of the United States, Ti-45Nb has replaced pure titanium for the manufacturing of rivet fasteners and has been widely used in factories. In areas with high shear strength requirements, bimetallic titanium rivets composed of Ti-6AI-4V nail rods and TI-45Nb heads are commonly used. The plasticity of TI-45Nb and the high strength of Ti-6A1-4V form a perfect combination, suitable for connecting titanium and composite components of various aircraft. This not only reduces weight, but also reduces costs. In recent years, this bimetallic rivet has also been widely used in China.

1.2 TB2 titanium alloy

TB2 titanium alloy material is the starting point of research on titanium alloy fasteners in China's aviation industry. In the 1960s, Chengdu Aircraft Design and Research Institute proposed the idea of using titanium alloy rivets, and began developing TB2 titanium alloy rivets in 1970. In 1979, the technical appraisal was finally completed and temporary technical conditions were formulated. TB2 titanium alloy is a type of metastable shaping β Titanium titanium has excellent cold forming and welding properties under solid solution treatment, and is currently used in the manufacturing of various cold heading rivets and some small size bolts in the aerospace industry. In the 1980s and 1990s, China successively issued three technical standards for TB2 titanium alloy rivets, including "Titanium Alloy Rivets", "Specification for Tensile Titanium Alloy Ring Groove Rivets", and "1000 Countersunk Head Tensile Titanium Alloy Ring Groove Rivets", which stipulated relevant technical specifications for use. At present, TB2 titanium alloy rivets have been widely used in China's aerospace industry due to their superior performance characteristics.

1.3 TB5 titanium alloy

TB5 titanium alloy is metastable β Type titanium alloy, with a nominal composition of Ti-15V-3Cr-3Sn-3A1, was first produced by the US Air Force research and development company YMET. TB5 titanium alloy has the same cold forming performance as pure titanium, capable of cold forming various complex parts in a solid solution state, and has excellent room temperature tensile strength and corrosion resistance. Its disadvantage is insufficient oxidation resistance, which is only suitable for environments below 200C. In practical applications, TB5 titanium alloy rivet fasteners are widely used in American B1B bombers, followed by Boeing aircraft. China also has certain applications for TB5 titanium alloy materials, such as satellite engine components and fighter plane flat beams.

Titanium alloy bolts are the most commonly used in the aerospace industry, including ordinary bolts, high lock bolts, and interference type bolts. The titanium alloy material used for manufacturing aviation bolts has high requirements for tensile and shear strength after heat treatment.

2.1 TC4 titanium alloy

TC4 titanium alloy was developed and manufactured by the United States in 1954, and has been widely used internationally. It is the most widely used titanium alloy and is not only used in aerospace manufacturing, but also widely used in industry. Such as the landing gear, bending gear, beams, fasteners, engine fans, blades, etc. of an aircraft. TC4 titanium alloy has ultra-high process resistance and can work for long periods of time in an environment of 400C. China began researching and applying TC4 in 1973, such as aircraft engine blades.

The bolts made of TC4 titanium alloy were first used in the manufacturing of 8-52 bombers in the United States in 1956, and their effectiveness was recognized and widely used in other countries. Currently, TC4 titanium alloy bolts are almost used in all aircraft manufacturing in developed countries. However, TC4 also has certain drawbacks, such as being unable to form by cold heading and having to undergo heat treatment, which requires high processing requirements. Therefore, China has developed a TC4 titanium alloy firmware hot heading machine tool and achieved industrial production. At present, TC4 titanium alloy bolts have been widely used in the manufacturing of space shuttles, passenger planes, satellites, and other industries in China.

2.2 TC6 titanium alloy

TC6 titanium alloy is a high-temperature resistant fastener material developed by the Beijing Institute of Aeronautics and Astronautics. It can work at high temperatures of 500C, but its manufacturing process requires certain difficulties. TC6 titanium alloy is a replica of BT3-1 titanium alloy from the former Soviet Union. It was first applied in aviation engine manufacturing in China in 1979, and then the development of TC6 titanium alloy bolts began. TC6 metal is a two-phase titanium alloy with good comprehensive performance, which can be used in the annealed state. It can also undergo some heat treatment strengthening, and has high oxidation and corrosion resistance. It can work for long periods of time in environments below 500 ° C. After warm annealing, the tensile strength is high, reaching over 980MPa, and it also has excellent properties such as elongation and reduction of area.

2.3 TB3 titanium alloy

TB3 was successfully developed in China in the 1970s. At that time, the 1100MPa titanium alloy bolts in developed industrial countries were all made of TC4 titanium alloy material. However, China's hot heading technology was not mature at that time and TC4 titanium alloy could not be used for manufacturing. Therefore, we developed a 1100MPa grade titanium alloy that can be directly connected to cold heading, also known as TB3 titanium alloy. This titanium alloy belongs to the metastable category β Type titanium alloy, capable of heat treatment strengthening, has strong cold forming ability in the solution treated state. After "solution+aging" treatment, it has high strength and can be used in the manufacturing of 1100MPa high-strength aerospace fasteners below 300C. China began to develop and form technical specifications in the 1980s, and then began to invest in the manufacturing of high lock bolts and interference type bolts. Currently, it has been widely used in the manufacturing of 100MPa bolts.

With the continuous development of the aerospace industry, titanium alloy fasteners have been widely used in aerospace manufacturing. Countries with developed aviation industries such as the United States and Russia have formed a titanium alloy fastener material manufacturing system. China's research on the application of titanium alloy fasteners in aviation manufacturing is relatively late, with most of it being improvements or imitations of Soviet technology, and the degree of application is relatively low. Therefore, it is necessary to accelerate the application research of titanium alloy materials for aviation fasteners in China and make contributions to the development of China's aviation industry.