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Dried food! An article on the current application status and development trends of new materials in the military industry
2022-8-19
Introduction: Military new materials can be divided into two categories based on their applications: structural materials and functional materials, which are widely used in fields such as aviation, aerospace, weapons, and ships. The article analyzes the relevant applications of the two in the military industry.
1、 Introduction
The country cannot stand without defense, and the people cannot be secure without defense. As a country and a nation, the most important things are nothing more than two major issues: development and security. National defense is a product of the development and security needs of human society, and it is a fundamental plan that concerns the survival of a country and a nation.
Modern national defense is centered around military forces and also includes relevant non military forces; It values the country's war potential, especially the mobilization efficiency during wartime; It is still a comprehensive competition based on economic and technological strength. As one of the most critical fields in the national science and technology development plan, materials technology, along with information technology, biotechnology, and energy technology, is widely recognized as a high-tech that will dominate the overall situation in today's society and for a considerable period of time in the future. High tech materials are still the key modern industrial technologies that support human civilization today. Military new material technology used in the military field is the material basis for developing high-tech weapons and the most important material foundation for a country's national defense.
For the sake of their own interests and the global situation, every country needs and must establish a strong national defense. Therefore, developing modern weapons with independent intellectual property rights is particularly important for national security. However, the current variety, specifications, performance, and smelting process of materials are far from meeting the needs of high-tech weapon development, and sometimes even become a bottleneck restricting weapon research and development. In this context, military material technology has emerged. At present, there are tens of thousands of military new material technologies worldwide, with an annual growth rate of 5%, developing towards high functionality, high energy, composite lightweight, and intelligence.
2、 The application of new material technology in military industry
Military new materials can be divided into two categories based on their applications: structural materials and functional materials, which are widely used in fields such as aviation, aerospace, weapons, and ships.
1. Military structural materials
With the development of modern science and technology, the technological intensity of weapons and equipment is increasing, evolving from mechanized warfare to information-based warfare, and weapons and equipment are developing towards precision guidance. Therefore, higher and updated requirements have been put forward for military materials.
1.1 Magnesium alloy
Magnesium alloy, as the lightest engineering metal material, has a series of unique properties such as light weight, high specific strength and stiffness, good damping and thermal conductivity, strong electromagnetic shielding ability, and good vibration reduction, which greatly meet the needs of military industries such as aerospace and modern weapons and equipment.
Magnesium alloy has many applications in military equipment, such as tank seat frames, rangefinder mirrors, gunner mirrors, gearbox housings, engine filter seats, inlet and outlet pipes, air distributor seats, oil pump housings, water pump housings, oil heat exchangers, oil filter housings, valve covers, respirators and other vehicle components; The support cabin section, aileron skin, wall panel, reinforcement frame, rudder board, partition frame and other missile components of tactical anti-aircraft missiles; Aircraft components such as fighter jets, bombers, helicopters, transport planes, airborne radars, surface to air missiles, carrier rockets, and artificial satellites. Magnesium alloy has the characteristics of light weight, good specific strength and stiffness, good vibration damping performance, electromagnetic interference, and strong shielding ability, which can meet the requirements of military products for weight reduction, noise absorption, shock absorption, and radiation protection. It occupies a very important position in aerospace and defense construction, and is a key structural material required for weapons and equipment such as aircraft, satellites, missiles, fighter jets, and tanks.
1.2 Aluminum alloy
Aluminum alloy has always been one of the most widely used metal structural materials in the military industry. Aluminum alloy material has the characteristics of low density, high strength, and good processing performance. As a structural material, due to its excellent processing performance, it can be made into various cross-sectional profiles, pipes, high reinforcement plates, etc., to fully tap the potential of the material and improve the rigidity and strength of components. Therefore, aluminum alloy is the preferred lightweight structural material for weapon lightweighting.
The development trend of aluminum alloys is to pursue high purity, high strength, high toughness, and high temperature resistance. The aluminum alloys mainly used in military industry include aluminum lithium alloy, aluminum copper alloy, and aluminum zinc magnesium alloy. The application of new aluminum lithium alloy in the aviation industry is expected to reduce aircraft weight by 8% to 15%; Aluminum lithium alloy will also become a candidate structural material for spacecraft and thin-walled missile shells. With the rapid development of the aerospace industry, the research focus of aluminum lithium alloys is still on solving the problems of poor toughness in the thickness direction and cost reduction.
1.3 Structural Ceramics
The commonly used structural ceramic materials mainly include: alumina, lead oxide, silicon nitride, silicon carbide, aluminum nitride, and their composite materials. Due to their high strength, hardness, high temperature resistance, corrosion resistance, and wear resistance, structural ceramic materials are widely used in the fields of national defense and military industry.
Ceramic materials are the fastest developing high-tech materials in the world today, and they have evolved from single-phase ceramics to multi-phase composite ceramics. Structural ceramic materials have good application prospects in the military industry due to their excellent properties such as high temperature resistance, low density, wear resistance, and low coefficient of thermal expansion. By utilizing the high hardness and wear resistance of structural ceramics, ceramic cutting tools, ceramic bearings, bulletproof armor, various valves, wear-resistant liners, and sealing rings can be prepared; The high-temperature resistance of structural ceramics can be utilized to prepare high-temperature ceramic heat exchangers, automotive exhaust filters, and high-temperature overcurrent components for gas turbines; The transparency of structural ceramics can be utilized to prepare transparent light tubes, missile window materials, etc.
1.4 High strength steel
High strength steel is steel with yield strength and tensile strength exceeding 1200MPa and 1400MPa, respectively. It is researched and developed to meet the high specific strength requirements of aircraft structures. High strength steel not only has high tensile strength, but also has certain plasticity and toughness, small notch sensitivity, high fatigue strength, certain corrosion resistance, good process performance, resource compatibility, and low price. Its application in the aviation industry is becoming increasingly widespread. High strength steel is widely used in the manufacture of rocket engine casings, aircraft fuselage skeletons, skins, and landing components, as well as high-pressure vessels and some conventional weapons. Due to the expansion of the application of titanium alloys and composite materials in airplanes, the amount of steel used in airplanes has decreased, but the key load-bearing components on airplanes are still made of high-strength steel. At present, 300M low-alloy high-strength steel, which is representative internationally, is a typical steel used for aircraft landing gear. In addition, low alloy high-strength steel D6AC is a typical material for solid rocket engine casing. The development trend of high-strength steel is to continuously improve toughness and corrosion resistance while ensuring high strength.
1.5 Advanced High Temperature Alloy
High temperature alloys are alloys that can withstand certain stresses at high temperatures of 600-1200 ℃ and have the ability to resist oxidation or corrosion. They have high high-temperature strength, good oxidation and corrosion resistance, good fatigue performance, fracture toughness, and other comprehensive properties. They are widely used as important materials in aviation, aerospace, petroleum, chemical, and shipbuilding industries.
According to the matrix elements, high-temperature alloys are further divided into iron-based, nickel based, cobalt based and other high-temperature alloys. Iron based high-temperature alloys can generally only reach temperatures of 750~780 ℃. For heat-resistant components used at higher temperatures, nickel based and refractory metal based alloys are used. Nickel based high-temperature alloys play a particularly important role in the entire high-temperature alloy field, and are widely used to manufacture the hottest end components of aviation jet engines and various industrial gas turbines. If the durability strength of 150MPA~100H is taken as the standard, and the current maximum temperature that nickel alloys can withstand is greater than 1100 ℃, while nickel alloys are about 950 ℃, and iron-based alloys are less than 850 ℃, that is, nickel based alloys are correspondingly higher by about 150 ℃ to 250 ℃. So people call nickel alloy the heart of the engine. At present, nickel alloys account for half of the total weight in advanced engines, not only in turbine blades and combustion chambers, but also in turbine disks and even in the later stages of compressor blades. Compared with ferroalloys, the advantages of nickel alloys are: higher working temperature, stable structure, fewer harmful phases, and greater resistance to oxidation and corrosion. Compared with cobalt alloys, nickel alloys can operate at higher temperatures and stresses, especially in the case of moving blades.
1.6 Composite Materials
Composite materials refer to materials composed of two or more substances with different properties or structures, usually consisting of a matrix material and a reinforcing agent. Advanced composite materials have higher comprehensive performance than general composite materials, including resin based composite materials, metal based composite materials, ceramic based composite materials, and carbon based composite materials. They play a crucial role in the development of military industry. Advanced composite materials have a series of advantages such as high strength, high modulus, erosion resistance, nuclear resistance, particle cloud resistance, wave transmission, absorption, stealth, and high-speed impact resistance. They are the most important type of engineering materials in the development of national defense industry.
Composite materials are rapidly developing into the fundamental structural materials of the aerospace industry. High performance polymer based composite materials account for 80% of their total usage in the aerospace industry. Due to the unique properties of carbon fiber, such as high specific strength, specific modulus, low thermal expansion coefficient, and high thermal conductivity, composite materials reinforced with it can be used as aerospace structural materials, with significant weight reduction effects and unparalleled potential for application. For example, carbon fiber reinforced resin based composite materials are used for space shuttle doors, robotic arms, and pressure vessels. In addition, they are also used for weight reduction of rockets and missiles, main load-bearing structures of aircraft, and radar wave stealth materials. In addition to coatings, composite materials are increasingly attracting attention as structural stealth materials, mainly carbon fiber reinforced thermosetting resin based composite materials (such as C/EP, C/PI, or C/BMI) and thermoplastic resin based composite materials (C/PEEK, C/PPS), which have been applied in some fields.
1.7 Intermetallic Compounds
Intermetallic compounds have long-range ordered superlattice structures that maintain strong metal bonding, giving them many unique physicochemical and mechanical properties. Intermetallic compounds have excellent thermal strength and have become an important new type of high-temperature structural material actively studied both domestically and internationally in recent years. In the military industry, intermetallic compounds have been used to manufacture components that withstand thermal loads; In the field of weapon industry, the turbocharger material for tank engines is K18 nickel based high-temperature alloy, which affects the acceleration performance of tanks due to its high specific gravity and large starting inertia. The application of titanium aluminum metal compounds and composite lightweight heat-resistant new materials reinforced with alumina and silicon carbide fibers can greatly improve the starting performance of tanks and enhance their survival ability on the battlefield. In addition, intermetallic compounds can also be used for various heat-resistant components, reducing weight, improving reliability and tactical indicators.
2. Military functional materials
Functional materials refer to materials that utilize effects such as sound, light, electricity, magnetism, heat, chemistry, and biochemistry to convert energy from one form to another. There are many functional materials, such as optoelectronic functional materials, hydrogen storage functional materials, damping and shock absorption materials, stealth materials, etc.
2.1 Optoelectronic functional materials
Optoelectronic functional materials refer to materials used in optoelectronic technology, which can transmit and process information by combining optoelectronics, and are an important component of modern information technology. Optoelectronic functional materials have a wide range of applications in the military industry. Mercury cadmium telluride and indium antimonide are important materials for infrared detectors; Zinc sulfide, zinc selenide, and gallium arsenide are mainly used to make windows, headgear, fairings, etc. for infrared detection systems of aircraft, missiles, and ground weapons equipment. Magnesium fluoride has high transmittance, strong resistance to rain erosion, and erosion, making it a good infrared transmission material. Laser crystals and laser glass are materials for high-power and high-energy solid-state lasers. Typical laser materials include ruby crystals, neodymium doped yttrium aluminum garnet, semiconductor laser materials, etc.
2.2 Hydrogen storage functional materials
Due to their unique lattice structure, certain transition cluster metals, alloys, and metal intermetallic compounds allow hydrogen atoms to easily penetrate into the tetrahedral or octahedral interstitial sites of the metal lattice, forming metal hydrides. These materials are called hydrogen storage materials.
In the weapons industry, lead-acid batteries used in tank vehicles require frequent charging due to their low capacity and high self discharge rate, making maintenance and transportation very inconvenient. The discharge output power is easily affected by battery life, charging status, and temperature. In cold weather conditions, the starting speed of tank vehicles will significantly slow down or even fail to start, which will affect the tank's combat capability. Hydrogen storage alloy batteries have the advantages of high energy density, overcharge resistance, earthquake resistance, good low-temperature performance, and long service life. They have broad application prospects in the future development of main battle tank batteries.
2.3 Damping and shock-absorbing materials
Damping refers to the phenomenon where the mechanical properties of a freely vibrating solid are converted into thermal energy even when completely isolated from the outside world. The purpose of using high damping functional materials is to reduce vibration and noise, so damping and shock-absorbing materials are of great significance in the military industry.
2.4 Stealth Materials
The development of modern attack weapons, especially the emergence of precision strike weapons, has posed a great threat to the survival of weapons and equipment. Relying solely on strengthening the protective capabilities of weapons is no longer practical. The use of stealth technology to render the enemy's detection, guidance, and reconnaissance systems ineffective, thereby concealing oneself as much as possible, seizing the initiative on the battlefield, and preemptively discovering and eliminating the enemy has become an important development direction for modern weapon protection. The most effective means of stealth technology is to use stealth materials.
Stealth materials include millimeter wave structural absorbing materials, millimeter wave rubber absorbing materials, and multifunctional absorbing coatings. They can not only reduce the probability of detection, tracking, and hit of millimeter wave radar and millimeter wave guidance systems, but also be compatible with visible light, near-infrared camouflage, and mid to far infrared thermal camouflage effects. In recent years, while improving traditional stealth materials, foreign countries have been committed to exploring various new materials. Whisker materials, nanomaterials, ceramic materials, chiral materials, conductive polymer materials, etc. are gradually being applied to radar wave and infrared stealth materials, making coatings thinner and lighter. Nanomaterials are being researched and developed as a new generation of stealth materials in developed countries due to their excellent absorbing properties, wide bandwidth, good compatibility, and thin thickness; The research on millimeter wave stealth materials in China began in the mid-1980s, with research units mainly focused on weapon systems. After years of effort, significant progress has been made in the pre research work, and this technology can be used for camouflage and stealth of various ground weapon systems, such as main battle tanks, 155mm advanced howitzer systems, and amphibious tanks.
At present, the 5th generation supersonic fighter aircraft under development in the world adopts composite materials, wing body fusion bodies, and absorbing coatings for its body structure, making it truly have stealth function. Electromagnetic wave absorbing coatings and electromagnetic shielding coatings have begun to be applied to stealth aircraft; The surface to air missiles of the United States and Russia are using stealth materials with high quality, wideband absorption, and good thermal stability. It can be foreseen that the research and application of stealth technology has become one of the most important topics in national defense technology around the world.
3、 The development trend of military new material technology
From the future development trend of military industry enterprises, new materials used in the military industry require high technological content. Military new materials worldwide are developing towards high functionality, high functionality, composite lightweight, and intelligence. The development of military high-tech requires materials to no longer be single structural materials. Under these conditions, military composite materials have emerged. The development direction of composite materials in the 21st century is low-cost, high-performance, multifunctional, and intelligent. After years of development, China's military materials have made significant progress, but there are also problems of "too much, too much, and too scattered". The poor serialization and generalization have affected the overall efficiency of military material research and the ability to support the development and production of weapons and equipment. Therefore, it is necessary to establish a military material system that is suitable for China's national conditions.
Looking back on the past, the development of national defense and the weapons industry has benefited from the advancement of materials science. Looking ahead, the progress of materials science will provide strong support for national defense construction.
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