The Application Of Titanium Alloy Materials In Aviation Fasteners

Titanium alloy has the advantages of good corrosion resistance, non-magnetic and high specific strength, which has quickly attracted the attention of the aviation sector and has been widely used.

1. Application of titanium alloy rivet fasteners in aviation industry

For rivets in the aviation industry, the cold plasticity of the material is very important, which is the premise of cold riveting installation. Titanium alloy rivets are usually used in parts with high corrosion resistance and low strength requirements.

1.1 Ti-45Nb alloy

The elongation of TI-45Nb can reach more than 20%, and it has good plasticity and cold working properties. Its shear and tensile strength are better than that of pure titanium, and its cold deformation resistance is lower than that of pure titanium. The best material choice for making rivets. In the aviation industry in the United States, Ti-45Nb has replaced pure titanium in the manufacture of rivet fasteners and has been widely used. In the parts with high shear strength requirements, the bimetal titanium rivets composed of Ti-6AI-4V nail rod and TI-45Nb head are generally used. The plasticity of TI-45Nb and the high strength of Ti-6A1-4V are formed. The perfect combination is suitable for the connection of titanium alloy components and composite material components of various aircraft, which not only reduces the weight, but also reduces the cost.

1.2 TB2 Titanium Alloy

TB2 titanium alloy is a metastable beta titanium alloy, which has excellent cold forming properties and welding properties under solution treatment. It is currently used in the manufacture of various cold heading rivets and some small-sized bolts in the aerospace industry.

1.3 TB5 Titanium Alloy

TB5 titanium alloy is a metastable β-type titanium alloy with a nominal composition of Ti-15V-3Cr-3Sn-3A1. TB5 titanium alloy has cold forming properties equivalent to pure titanium, can be cold forming of various complex parts in solid solution state, and has excellent room temperature tensile strength and corrosion resistance, its disadvantage is insufficient oxidation resistance, only Suitable for environments below 200C.

2. Application of titanium alloy bolt fasteners in aviation industry

Titanium alloy bolts are the most used in the aerospace industry, including ordinary bolts, high-lock bolts and interference bolts. The titanium alloy material used to manufacture aviation bolts has high requirements on tensile strength and shear strength after heat treatment.

2.1 TC4 titanium alloy

TC4 titanium alloy was researched and manufactured by the United States in 1954, and has been widely used internationally, not only in aerospace manufacturing, but also in industry. Such as aircraft landing gear, truss, beams, fasteners, engine fans, blades, etc.

At present, TC4 titanium alloy bolts are used in almost all aircraft manufacturing in developed countries. However, TC4 also has certain shortcomings, such as the inability to cold heading, only heat treatment, and the processing technology requirements are higher.

2.2 TC6 titanium alloy

TC6 titanium alloy is a high temperature resistant fastener material developed by Beijing Institute of Aeronautics and Astronautics. It can work at a high temperature of 500C, but its manufacturing process requires a certain degree of difficulty. TC6 titanium alloy is an imitation of the former Soviet Union BT3-1 titanium alloy. TC6 titanium alloy has good comprehensive properties, can be used in annealed state, can also be strengthened by some heat treatment, has high anti-oxidation and anti-corrosion properties, and can work for a long time in an environment below 500″C , The tensile strength after warm annealing treatment is high, reaching more than 980MPa, and it also has excellent elongation, section shrinkage and other properties.

2.3 TB3 titanium alloy

TB3 titanium alloy is a metastable β-type titanium alloy, which can be strengthened by heat treatment. It has strong cold forming ability in the state of solution treatment, and has high strength after “solution + aging” treatment. It can be used for the manufacture of 1100MPa grade high strength aerospace fasteners up to 300C.

3. Conclusion

With the continuous development of aerospace industry, titanium alloy fasteners have been widely used in aerospace manufacturing. The United States, Russia and other countries with developed aviation industries 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, most of which are improvements or imitations of the former Soviet Union technology, and the degree of application is relatively low. Therefore, it is necessary to speed up the titanium alloy materials for aviation fasteners in China. applied research and contribute to the development of China’s aviation industry.