Since the beginning of the 20th century, the world has been swept by the tide of space exploration and great powers have entered this field.
The field of human space exploration has seen great opportunities for development, from satellite manufacturing to human spaceflight. However, despite our many achievements, we still face many difficulties and challenges and research into various technologies is still at an early stage.
One of the significant difficulties in the aerospace area is the selection of aerospace materials, which greatly impacts its development.
This article aims to provide information on metal alloy materials suitable for the aerospace field and focuses on magnesium alloy.
After extensive exploration, magnesium alloy was chosen as a key component of aerospace materials. This article discusses the strict living environment requirements of spacecraft in space, the exceptional properties of magnesium alloys, and the reason why magnesium alloys are suitable for manufacturing spacecraft in the aerospace field.
(1) High density
The challenge of reducing fuel load has been a pressing issue in the aerospace industry.
Among the available engineering metal alloys, magnesium alloy stands out for its low density of approximately 1.8g/cm3, which is about two-thirds that of aluminum and a quarter that of steel.
This low density makes the use of magnesium alloy in the aerospace industry viable.
With the lightest specific gravity of all structural alloys, magnesium alloy allows weight reduction in aluminum or iron parts without sacrificing strength.
Therefore, magnesium alloys, being lightweight, are widely used in aerospace applications.
This not only greatly reduces the weight of the aircraft fuselage, but also significantly reduces the fuel load, causing a significant impact on the aircraft's flight.
(2) High strength ratio
Magnesium alloys have high specific strength and density.
Compared to aluminum and steel alloys, magnesium alloys have superior properties in terms of specific strength and density.
Therefore, magnesium alloy materials can be used in aircraft assembly to produce components that need to withstand heavy loads, such as spacecraft cabins and engine parts.
(3) Good heat dissipation
Compared to other alloys, magnesium alloys have a clear advantage in terms of heat dissipation.
This is because the difference in air temperature between the base and top of a heatsink made from magnesium alloy is significantly greater than that of heatsinks made from other alloys, leading to faster air diffusion into the radiator. convection and greatly improving radiator heat. dissipation efficiency.
At a constant temperature, a radiator made from magnesium alloy takes half as long to dissipate heat as one made from aluminum alloy.
(4) Good shock absorption effect
In the elastic range, when subjected to impact, magnesium alloys undergo relatively small elastic deformation and absorb a large amount of energy, leading to reduced vibration during impact.
As a result, magnesium alloys have good shock absorption capacity.
This also leads to a reduction in noise generated by collisions, making magnesium alloys have excellent noise reduction performance. This can effectively mitigate various adverse effects of noise on aircraft.
The exceptional shock absorption and noise reduction capabilities of magnesium alloys are essential to ensuring aircraft safety.
(5) Good remodeling
In the early 1900s, die casting technology was applied to form magnesium alloy materials.
However, traditional die casting methods had limitations in removing surface defects and improving the internal quality of castings. As a result, efforts have been made to improve the process and advance magnesium alloy die casting technology.
Magnesium alloys have favorable remolding properties, making them ideal for manufacturing structural parts with complex shapes and small load capacities, such as engine and brake accessories.
(6) Corrosion resistance
The impact of various media and atmospheric conditions on materials mainly manifests as corrosion and aging.
Aerospace materials are exposed to contact with aircraft fuels (such as gasoline and kerosene), rocket propellants (such as concentrated nitric acid, nitrogen tetroxide and hydrazine), various lubricants and hydraulic oil, among others.
Most of these substances have strong corrosive or expansive effects on metallic and non-metallic materials.
The aging process of polymeric materials can be accelerated by prolonged exposure to mold in the atmosphere, mold erosion caused by wind and rain, and mold in humid underground environments.
Therefore, resistance to corrosion, aging and mold are essential properties of aerospace materials.
Magnesium, being the most reactive metal, makes magnesium alloys susceptible to corrosion due to reactions on its surface, causing significant damage.
As a result, the protection of magnesium alloy surfaces is of great importance.
In the past, magnesium alloys were mainly protected through chemical oxidation, but with the rapid development of anodic oxidation technology in the 1980s, this method replaced traditional chemical oxidation.
In the research on CO 2 +SF 6 gas atmospheric smelting technology and the protection mechanism of SF 6 gas magnesium alloy matrix, it is found that a priority layer and the form of Mg film will be generated on the surface of the magnesium alloy.
The F ions can be used as MgO medium particles and the internal liquid Mg to generate even more MgF 2 .
The material will protect the existence between the film and the matrix, making the protective film more compact.
Due to environmental problems, researchers are also looking for other gases with less pollution and that also contain F to replace SF 6 .
Magnesium alloys are highly susceptible to corrosion from many alkaline substances, while spacecraft exhibit strong stability in alkaline environments.
(7) Some chemical properties are stable
Magnesium alloys show strong stability in some organic compounds, such as gasoline and kerosene.
Therefore, magnesium alloys can be used in the manufacture of fuel tanks for gasoline and kerosene, as well as in components that come into contact with gasoline, such as engine gears and brakes.
Magnesium alloy products are widely used in civil and military aircraft, especially bombers. For example, the body of the B-25 bomber is built from magnesium alloy, with 90kg of extruded parts and more than 200kg of castings.
Magnesium alloys are also used in missiles and some satellite components, such as the instrument cabin, rear cabin and engine mount of China's Red Flag surface-to-air missile.
(8) Temperature resistance Magnesium alloy has certain resistance to high and low temperatures and can generally adapt to the living environment of spacecraft in the air.
Other metallic materials are prone to melting in certain high-temperature areas of space.
The high temperature resistance of magnesium alloys ensures that they can withstand high temperatures.
At the same time, aluminum alloys have the ability to adapt to low-temperature environments and exhibit strong thermal insulation properties, protecting the normal operation of aircraft internal components.
Magnesium alloys also have good mechanical properties at high temperatures and have excellent mechanical properties in space, providing a solid foundation for space flight.
In the aerospace industry, material requirements for aircraft production are extremely stringent, and each part of the aircraft must meet strict standards.
Meeting these requirements with industrial materials can be challenging. However, the excellent properties of magnesium alloys align well with the aerospace industry's needs for spacecraft manufacturing materials.
Magnesium alloys are suitable for a wide range of applications, from body parts to engine parts.
Magnesium's high density significantly reduces the spacecraft's fuel load, enabling longer flight times.
The high specific strength and specific stiffness ensure the stability of the spacecraft and provide excellent defense capabilities in space.
Its good modification properties support the manufacturing of spacecraft components.
Its high damping effect provides a reliable guarantee for spacecraft.
With its corrosion resistance, high temperature resistance and strong compatibility with aluminum alloys, magnesium alloys have great potential in space.
The excellent properties of magnesium alloys make them an important player in the aerospace industry.
