Titanium for use on American spacecraft

Titanium was widely used in spacecraft in the United States, where the Mercury spacecraft was developed in 1972 and launched for the first time in 1981 to carry a man into space.The spacecraft has a mass of 2T and is bell shaped. It is divided into three parts: the base part, the sealed compartment (pressure compartment) and the top part.The volume of the pressure chamber is 1.4m3, and the main structure is made of titanium alloy, accounting for about 80% of the total weight of the structure, weighing 168kg, and the amount of titanium material is about 240kg (purchase quality).The inner skin is welded with pure titanium sheet with a thickness of 0.25mm, and the reinforcement is extruded with Ti-5Al-2.5Sn titanium alloy, which has medium mechanical strength. Part of the skeleton ring is made of Ti-6Al-4V alloy, on which the inner mask leather plate is welded.Ti-6Al-4V is one of the most used titanium alloys, is a very good comprehensive alloy, not only has high mechanical properties, but also can be used at 480℃ for a long time, high heat resistance, good weldability, welding seam has excellent air tightness, to adjust the cabin pressure is very beneficial.This kind of spaceship is used Atlas rocket to launch, the rocket many structure parts, such as the stiffening ring, the connection ring and so on is made of titanium alloy.The composition (mass %) of Ti-5Al-2.5Sn alloy: Al4.5 ~ 5.75, Sn2.0 ~ 3.0, Fe0.50, C0.08, N0.05, H0.020, O0.20.

In 1984, "Gemini" spacecraft launched, is an improved version of "Mercury" spacecraft, is also bell shaped, but the amount and varieties of titanium alloy more, sharing 7 kinds, titanium structure of the net mass of about 570kg, accounting for 84% of the structure of the net mass.The inner wall of the spacecraft is a double layer, with 0.25mm thick industrial pure titanium plate welded.Ti-6Al-4V titanium alloy spherical pressure vessel, its tensile strength can reach 900MPa;Landing gear structural parts are heavily stressed and forged with high strength Ti-7AI-4MO titanium alloy, whose tensile strength can reach 1100MPa or more.

The spacecraft had to slow down as it re-entered the atmosphere. This task was accomplished by four round rockets loaded with solid fuel. Each rocket had two titanium alloy semi-spheres welded by Ti-6Al-4V, 1.0mm thick, with a strict deviation of +0.17mm and -0.01mm.The oxygen cylinder in the crew room is made of Ti-6Al-4V or Ti-13V-11Cr-3Al titanium alloy.The oxygen cylinder has a volume of 2.5L, a pressure of 2059MPa and a mass of 160kg.

The Apollo spacecraft.The ship is similar to Chang 'e-5, the Chinese space agency's lunar exploration program, which will be launched in 2020.But Chang 'e 5 carried no people, while Apollo sent people to the moon, landed on the lunar surface and then returned to Earth. It consisted of a spacecraft hull and a large Saturn V rocket with a mass of 50 tons and a mass of 2,900 tons.The spacecraft contains a 7.65m3 command module, a mechanical module and a lunar module.The spaceship and the rocket structure shared 68 tons to process titanium.All of the carrier's brackets, fixtures and fasteners are titanium.The command module, mechanical module and lunar module shared 1,190kg of titanium.

The tower structure of the launch and traction system is made of titanium alloy, the liquid hydrogen container and conduit of the command module and mechanical module, and the cryogenic container of the lunar module are all made of Ti-6Al-4V alloy.The container of the landing part of the lunar module needs to have greater plasticity, so it is made of Ti-5Al-2.5Sn alloy.Apollo has more than 40 pressure vessels, of which about 85% are made of titanium alloy, using Ti-6Al-4V and Ti-5Al-2.5Sn alloys to make nitrogen tetroxide, helium, nitrogen and fuel containers.Liquid hydrogen and supercritical helium vessels are made of Ti-5Al-2.5Sn alloy because of its high toughness at -252.7℃.

Space shuttle is the communication between the ground and the space station transportation, so also known as space ferry, requirements can be used many times, the best can reach 100 times or more, it in the atmosphere, the upper half of the fuselage and wing temperature can reach 180℃ ~ 815℃, therefore, some parts of the components need to be made of heat-resistant titanium alloy,For example on the fuselage frame with Ti/B - Al composites, rear wing, wing beams and floor are made of titanium alloy preparation, hydraulic piping for Ti - 3-2.5 V alloy seamless tube, and make the system reduced more than 40%, the quality of in order to reduce the sensitivity of the fatigue fracture and improve the system of service period, forming and assembly of all kinds of pipe fittings are automatic.