Materials are the material basis of human existence. The continuous development and progress of human society lies in the fact that human beings can make tools with materials and transform the world with tools. Engels said: "Nature provides material for labor, and labor turns material into wealth." It can be said that materials are closely related to the survival and evolution of human beings, so they are known as "the cornerstone of the building of human civilization".
Materials, such as ordinary steel, cement, glass, etc. It is easy to understand and belongs to traditional materials. Compared with traditional materials, new materials, also known as advanced materials, refer to new materials that have been successfully researched or are being developed recently and have excellent characteristics and functions, and can meet the requirements of high technology.
The development of human history shows that materials are the material basis and forerunner of social development, while new materials are the milestone of social progress. Material technology has always been a very important field in the scientific and technological development planning of all countries in the world. Together with information technology, biotechnology and energy technology, it is recognized as a high-tech that will dominate the overall situation of mankind in today's society and for a long time to come. High-tech materials are also the key technology to support modern industry of today's human civilization and the most important material foundation of a country's national defense force. The defense industry is often the first user of new materials and technological achievements. The research and development of new material technology plays a decisive role in the development of national defense industry and weapons and equipment.
New materials are not only the foundation of scientific and technological development, but also the forerunner of scientific and technological progress, which are two remarkable characteristics of new materials. For example, the discovery and development of semiconductor materials have greatly promoted the progress of computer technology and brought mankind into the information age; The development of optical fiber technology has promoted the progress of modern communication technology; The emergence of new structural materials and ablative thermal protection materials has promoted the development of space technology and strategic weapons.
In the strategic planning system of national defense science and technology for 2 1 century formulated by the U.S. Department of Defense, materials and preparation technology are identified as one of the four priority areas, and five key points are put forward, including structural and multifunctional materials technology, energy and power materials technology, optoelectronic materials technology, organic and synthetic functional materials technology, and bio-derived and bio-induced materials technology. Germany analyzed the development trend of high technology in the world, and put forward nine key fields in 2 1 century, with new materials as the first choice. Of the 80 R&D projects, 24 are related to new materials.
Undoubtedly, new materials have become an important field of comprehensive national strength competition and an important material foundation of national defense forces, and are the material support for improving the level of military mechanization and the basic conditions for improving the level of informationization. Therefore, many countries give priority to the development of new materials, especially the development of new military materials technology.
Second, all kinds of new materials.
At present, the development of new materials focuses on structural materials with excellent performance and functional materials with specific functions, mainly including advanced composite materials, special metal materials, special polymer materials, biomedical materials and invisible materials.
1. Advanced composites
Advanced composite material refers to an advanced material composed of two or more materials with different properties. Advanced composite materials are the main development direction of structural materials. This material is characterized by high strength, low specific gravity, good aeroelasticity and mass production. Composite materials have been widely used in aerospace industry and various weapons and equipment. Advanced composite materials have been successfully applied to military aircraft such as F- 16, F- 18, Mirage 2000, strategic missiles such as militia, Trident and Dwarf, and tanks such as M- 1, T-72 and Leopard -II.
For example, the AV-8B VTOL aircraft in the United States used this material, and its weight was reduced by 27%. The number of F- 18 fighters decreased by 10%, thus greatly improving the maneuverability of the aircraft. Modern ships made of composite materials have greatly reduced their self-weight, greatly improved their speed, and enhanced their maritime mobile combat capability. In 1970s, Britain developed Chom composite armor and applied it to a new generation of tanks. This armor has three layers, the outer layer and the inner layer are made of metal materials such as steel, aluminum alloy or iron alloy, and the middle layer is made of nonmetal materials such as plastic, ceramics and glass fiber. Its armor-piercing prevention and armor-piercing ability is obviously superior to traditional homogeneous armor.
In order to further promote the application of composite materials in weapons and equipment, the United States is implementing the "Advanced Design Composite Aircraft" program. It is estimated that composite materials will account for 68.5% of the structural mass of aircraft and reduce the overall structural mass by 35%.
2. Special metal materials
The representatives of special metal materials are titanium alloy, shape memory alloy and hydrogen storage metal, all of which have their own specialties.
(1) titanium alloy
This alloy has low density, high strength, excellent corrosion resistance and high temperature resistance, and is an ideal lightweight structural material. The application of titanium alloy in aviation industry is mainly to manufacture aircraft fuselage structure, landing gear, support beam, engine compressor disk, blades and joints. Since 1970s, the use of titanium alloys in military aircraft and engines has increased rapidly, from fighter planes to large military bombers and transport planes. Its consumption in F- 14 and F- 15 fighters accounts for 25% of the structural weight, and its consumption in F- 100 and F-39 fighter engines reaches 25% and 33% respectively. After the 1980s, titanium alloy materials and technology developed further, and a B-LB aircraft needed 90,402 kilograms of titanium alloy materials. At the same time, titanium alloys are increasingly favored by the military. Lightweight of heavy equipment such as army self-propelled artillery and armored vehicles can greatly improve mobility. It is the inevitable trend of weapon development. On the premise of ensuring the maneuverability and protective performance of weapons, titanium alloys are widely used in army weapons. For example, the brake of 155 gun adopts titanium alloy, which can not only reduce the weight, but also reduce the deformation of barrel caused by gravity, and effectively improve the shooting accuracy; Some parts with complex shapes on main battle tanks, helicopters and anti-tank multi-purpose missiles can be made of titanium alloy, which can not only meet the performance requirements of products, but also reduce the processing cost of parts.
(2) Shape memory alloy
1932, the Swede Aurand first observed the "memory" effect in the Au-Cd alloy, that is, once the alloy is heated to a certain transition temperature, it can magically change back to its original shape. People call the alloy with this special function shape memory alloy. The development of memory alloy is only over 20 years, but because of its special functions in various fields, it has attracted worldwide attention and is known as "magical functional materials".
Shape memory alloys can be divided into three types: one is unidirectional memory alloy, which deforms at low temperature and can recover after heating. This shape memory phenomenon, which only exists in the heating process, is called one-way memory effect. The second type is bidirectional memory alloy, which deforms at low temperature, and will return to its shape at high temperature once heated, and will return to its shape at low temperature once cooled. This shape memory phenomenon during heating and cooling is called bidirectional memory effect. The third type is full memory metal, which can return to the shape at high temperature when heated and become the shape at low temperature after cooling, which is called full memory effect.
Shape memory alloys have been used in aerospace equipment. For example, the low-temperature bonding connector used in the hydraulic system of military aircraft, and the shape memory alloy material for the intelligent horizontal rotor of helicopter is being developed in Europe and America. Because the use of helicopter high vibration and noise is limited, the main sources of noise and vibration are blade eddy current interference and slight deviation of blade profile. This requires a device to balance the pitch of the blades so that each blade can rotate accurately in the same plane. At present, a blade trajectory controller has been developed, which uses a small dual-tube shape memory alloy actuator to control the position of winglet on the blade edge trajectory to minimize its vibration.
Scientists also use memory alloys to make aerial refueling interfaces. After the aerial tanker is connected with the refueling pipeline of a combat aircraft, the temperature can be changed by electric heating, so that the memory alloy at the interface can be deformed and the oil drips tightly.
There are many successful examples of the application of memory alloys in the aerospace field. There are several hundred square meters of self-expanding antennas on the space station. This kind of antenna cannot be sent into space by existing spacecraft without "reducing deformation". With the memory alloy, the problem will be solved. Using memory alloy, humans first made a large-area parabolic or planar antenna on the ground, and then folded it into a ball and carried it into space by spacecraft. When the antenna is irradiated by the sun, its temperature changes. Because of its "memory" function, the folded antenna naturally unfolds and recovers its parabolic shape.
(3) Hydrogen storage metal
You may have learned a lot about the chemistry of hydrogen. Hydrogen can be burned and is a kind of fuel with high calorific value. Burning 1 kg hydrogen can release 143283200 joules of heat, which is incomparable in conventional fuels! Moreover, in the combustion process, hydrogen and oxygen combine to generate water, which will not cause any pollution to the environment. Therefore, hydrogen can be said to be the cleanest fuel.
There are many ways to produce hydrogen, such as electrolyzing water, but it consumes a lot of energy. In general, it is uneconomical to produce hydrogen as fuel by electrolytic water method. Therefore, scientists are studying more economical methods to produce hydrogen, and one of the most striking methods is called photolysis. Sunlight is an inexhaustible source of natural gas energy. Using sunlight to decompose seawater may be the most promising way for us to find pollution-free energy. However, new problems have emerged.
At present, steel high-pressure container-hydrogen bottle is generally used to store hydrogen. Even if the hydrogen in the bottle is increased to 150 atmospheric pressure, the weight of hydrogen contained in the bottle is less than1100 of the weight of the gas cylinder, and there is a danger of explosion. Obviously, this storage method is not suitable for the large-scale use of hydrogen in industry and life. While people are thinking hard about solving the problem of hydrogen storage, the latest research results of metal materials bring us hope.
Scientists have found that some metals have the ability to capture hydrogen. These metals are called "hydrogen storage" metals. They can absorb a lot of hydrogen at a certain temperature and pressure higher than the equilibrium pressure, and a metal atom can combine with two, three or even more hydrogen atoms to form metal hydride. When we heat this metal hydride, it will decompose and release hydrogen. Theoretically, some metals equivalent to the weight of hydrogen bottle1/can "absorb" hydrogen equivalent to the hydrogen storage capacity of hydrogen bottle, but their volume is smaller than that of hydrogen bottle110. Many metals and alloys with hydrogen storage capacity have been found, among which Ti-Fe alloy, La-Ni alloy and Mg-Ni alloy are close to practical use.
The method of storing hydrogen has been found, and the application of hydrogen as fuel will be more extensive. If hydrogen is used as fuel instead of gasoline, it can be used in various internal combustion engines, and it doesn't need to make much changes to the existing internal combustion engines, and it can even improve the efficiency by 40%!
Hydrogen storage metals have the unique advantages of high hydrogen purity, high hydrogen storage density, good safety and long service life, so they are quickly favored in the military field. For example, in the weapon industry, lead-acid batteries used in tanks and vehicles need to be recharged frequently because of their low capacity and high self-discharge rate, which is very inconvenient to maintain and carry at this time. The discharge output power is easily influenced by battery life, charging state and temperature. In cold weather, the starting speed of tank vehicles will obviously slow down or even fail to start, which will affect the combat capability of tanks. Hydrogen storage alloy battery has the advantages of high energy density, overcharge resistance, earthquake resistance, good low temperature performance and long service life, and will have broad application prospects in the future development of main battle tank batteries. If hydrogen storage metal is used as the fuel of combat aircraft, it can greatly improve the payload, speed and range of the aircraft, reduce noise and increase the concealment of the combat aircraft.
(4) Superconducting materials
19 1 1 year, Dutch physicist Anis (1853 ~ 1926) found that the resistivity of mercury did not decrease gradually with the decrease of temperature as expected, but when the temperature dropped to a certain value, the resistance of mercury suddenly dropped to zero. When the temperature of some metals, alloys and compounds drops to a certain temperature close to absolute zero, the phenomenon that their resistivity suddenly drops to unmeasurable is called superconductivity, and substances that can conduct superconductivity are called superconductors. The temperature at which a superconductor changes from a normal state to a superconducting state is called the transition temperature (or critical temperature) of this substance. It is found that most metal elements and thousands of alloys and compounds show superconductivity under different conditions.
Superconducting materials are quite different from conventional conductive materials in performance. 1. Zero resistance: When superconducting materials are in superconducting state, the resistance is zero, which can transmit electric energy thousands of miles away without loss. If a magnetic field is used to induce an induced current in the superconducting ring, the current can remain undiminished. This "continuous current" has been observed many times in experiments. The second is complete diamagnetism: when the superconducting material is in superconducting state, as long as the applied magnetic field does not exceed a certain value, the magnetic field lines cannot penetrate, and the magnetic field in the superconducting material is always zero. The third is Josephson effect: a thin insulating layer (about 1 nm thick) is added between two superconducting materials to form a low resistance, and electron pairs will pass through the insulating layer to form a current, but there is no voltage on both sides of the insulating layer, that is, the insulating layer becomes a superconductor. When the current exceeds a certain value, voltage U appears on both sides of the insulation layer, and at the same time, DC current becomes high-frequency alternating current, radiating electromagnetic waves. The above three characteristics make superconducting materials become functional materials that many countries invest a lot of manpower and material resources in research, and try their best to use them for military purposes.
Application of superconducting technology in ships. The United States, Britain, Japan and other countries began to study the application of superconducting technology in naval vessels in the 1970s, and achieved initial results. At present, three superconducting electromagnetic propulsion ships have been successfully tested in the world. Superconducting electromagnetic force propulsion device is designed according to electromagnetic principle. An electromagnet was installed on the ship. Under the interaction of magnetic field and current, seawater moves backward. Under the reaction of seawater, the ship will get forward thrust. Superconducting ships need neither engine nor propeller, which can effectively eliminate noise and reduce infrared radiation, thus greatly improving the survivability, rapid maneuverability and penetration ability of naval ships.
Application of superconducting technology in fighter. High power and small volume engine is the key factor to improve the combat performance of combat aircraft. With the continuous breakthrough of superconducting technology, it provides conditions for the development of large-capacity and miniaturized MHD generators. Once the superconducting generator is put into practical use, it can provide efficient power for large-scale radar, large-scale computer, various communication equipment and other very power-consuming equipment in the air command post and front engine.
Application of superconducting technology in military reconnaissance, communication, electronic countermeasures and command. Instruments and equipment made of superconducting material "Josephson effect" have the characteristics of high sensitivity, low noise, fast response and low energy consumption, and are of great use in military reconnaissance, communication, electronic countermeasures and command.
Military superconducting communication can realize long-distance and large-capacity communication by using superconducting wires. Research and experiments show that superconducting wires can transmit information much faster than optical fiber systems, and can transmit trillions of pulses per second. Scientists predict that in the future, the capacity of high superconducting long-distance communication will be several hundred times larger than that of optical cable, and the information equivalent to 1000 encyclopedias can be transmitted every second. At the same time, because the superconducting wire has no loss, the amplifier can be omitted every 3 ~ 4 kilometers.
Military superconducting radio communication, using superconducting materials to make radio transmitters and receivers, not only has high sensitivity and wide bandwidth, but also can reduce the size and weight of the antenna and improve the survivability of the system. The transmission distance of the world's first superconducting radio transmitter manufactured by Birmingham University in the UK is 10 times longer than that of conventional transmitters. Superconducting materials are also ideal materials for manufacturing communication satellites, which can improve the speed of information processing and shorten the frequency response time by half. Using superconducting materials to make satellite antennas can improve their efficiency by 90%.
Automated military command system needs to process a large amount of information at high speed. Using superconducting materials with zero resistance to make computers, due to the reduction of power consumption, the heat generated by the circuit can be ignored, the operation speed is greatly improved, and the volume and weight can also be greatly reduced. The 4-bit superconducting microprocessor developed by Fujitsu Company of Japan is 10 times faster than similar processors using gallium arsenide technology, and the power consumption is only 1/500 times lower. It is said that if computers are made of superconducting materials, the current billion supercomputers can be made as big as mini personal computers. The application of this high-speed microcomputer will greatly improve the efficiency of military command and the performance of weapon guidance system.
The detector using superconducting technology is extremely sensitive to magnetic field and electromagnetic radiation, and its sensitivity is thousands of times higher than that of conventional detectors. It is an ideal equipment for military remote sensing reconnaissance. There are mainly space-based staring infrared focal plane array detectors, microwave and millimeter wave detectors, magnetic detectors and so on. Superconducting detectors are not only small in size, light in weight, long in operating range and high in detection sensitivity, but also have all-weather and smoke-penetrating detection capabilities that ordinary visible light and infrared detection systems do not have, and can provide detection capabilities for low-feature targets, which can be widely used in spacecraft phased array antennas, anti-submarine weapons and mine detection.
It is reported that a new generation of superconducting radar is also under development. Its antenna, transmitter, receiver, frequency stabilizer, signal simulator, filter and other electronic devices are all made of high superconducting materials, which has the advantages of low power consumption, low noise, wide band, high sensitivity, high reliability, small size and light weight. Superconducting electronic devices used in radar system can expand the radar spectrum by 166 times, increase the range by one order of magnitude, and detect weak signals.
3. Special polymer materials
Polymer materials are materials composed of relatively high molecular weight compounds. Many natural materials we come into contact with are usually made of polymer materials, such as natural rubber, cotton, human organs and so on. The same is true of synthetic chemical fibers, plastics and rubber.
Polymers are forms of life. All living things can be regarded as a collection of polymers. Natural polymer materials such as branches, hides and straws are the first materials used by human beings. In the long history, paper, gum, silk and other products processed from natural polymer materials are intertwined with the development of human civilization.
Since19th century, human beings have started to use modified natural polymer materials. Cremation rubber and nitrocellulose plastic (celluloid) are two typical examples. After entering the 20th century, polymer materials entered a stage of great development. In the late 1920s, PVC began to be used on a large scale. In the early 1930s, mass production of polystyrene began. In the late 1930s, nylon began to be produced. After the great development of the 20th century, polymer materials have had an important impact on the whole world. Time magazine thinks that plastic is the most important invention of mankind in the 20th century. Polymer materials have also had an important impact on the cultural field and human lifestyle. General polymer materials are generally divided into five categories according to their uses, namely plastics, rubber, fibers, coatings and adhesives.
Polymer materials not only play an important role in people's daily life, but also have a wide range of military applications, and the consumption in military equipment is second only to steel materials. In terms of individual protective equipment, the most typical application mode is various fiber products (such as military uniforms and tents) used by soldiers in peacetime and wartime, which are used in shoes and boots, waterproof and impact-resistant structural layers, life-saving buoyancy materials, load-bearing parts and connectors in the form of rubber and plastic. In terms of heavy weapons and equipment, it can replace high-strength alloy to manufacture military aircraft, tanks and other heavy equipment, greatly reducing the weight of weapons. Polymer materials with strong bonding function can also be widely used to bond weapon parts, especially rocket and missile parts with a large proportion of nonmetal.
4. Biomedical materials
Biomedical materials are a kind of materials developed for repairing or replacing diseased organs to restore human functions. Biomedical materials are the basis of studying artificial organs and medical devices, and have become an important branch of materials science. Especially with the vigorous development and major breakthrough of biotechnology, biomaterials have become the focus of research and development by scientists all over the world. Contemporary biomaterials are about to make a major breakthrough. In the near future, it is possible for scientists to design and manufacture whole human organs with the help of biomaterials. It can be predicted that in the future battlefield, many soldiers injured by shrapnel will recover quickly through biomedical materials and rejoin the battle quickly.
5. Stealth materials
The development of modern attack weapons, especially the appearance of precision strike weapons, has greatly threatened the survivability of weapons and equipment, and it is unrealistic to rely solely on strengthening the protection capability of weapons. Using stealth technology to disable the enemy's detection and reconnaissance system, so as to hide yourself as much as possible, grasp the initiative in the battlefield, find and destroy the enemy first, has become an important development direction of modern weapon protection. The most effective means of stealth technology is to use stealth materials. Foreign research on stealth technology and materials began in Germany during the Second World War, developed in the United States and extended to Britain, France, Russia and other countries. At present, the United States is at the leading level in stealth technology and material research. In the aviation field, many countries have successfully applied stealth technology to aircraft stealth; In terms of conventional weapons, the United States has also done a lot of work in the stealth of tanks and missiles, and has used them in equipment one after another. For example, MlAl tanks in the United States used radar wave and infrared wave stealth materials, and T-80 tanks in the former Soviet Union were also coated with stealth materials.
In recent years, while improving traditional stealth materials, many new materials are being explored abroad. Whisker materials, nano-materials, ceramic materials and conductive polymer materials are gradually applied to radar wave and infrared wave stealth, making the coating thinner and lighter. Nano-materials have become a new generation of stealth materials developed by developed countries because of their excellent absorbing characteristics, wide frequency band, good compatibility and thin thickness. The research of millimeter wave stealth materials in China began in the mid-1980s, and the research units mainly focused on weapon systems. After years of efforts, great progress has been made in scientific research. This technology can be used for camouflage and stealth of various ground weapon systems, such as main battle tanks, 155 mm advanced howitzer systems, amphibious tanks, etc.
At present, stealth aircraft have been coated with electromagnetic wave absorption coating and electromagnetic shielding coating; Stealth materials with light weight, broadband absorption and good thermal stability are used in surface-to-air missiles of the United States and Russia. It can be predicted that the research and application of stealth technology has become one of the important topics of national defense technology in the world.
6. Photoelectric materials
Optoelectronic materials refer to materials used in optoelectronic technology and are an important part of modern information technology. Photoelectric materials are widely used in 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 manufacture windows and hoods of infrared detection systems such as airplanes and missiles. Magnesium fluoride is a good infrared transmission material with high light transmittance and strong resistance to rain erosion and erosion. Laser crystal and laser glass are materials for high-power and high-energy solid-state lasers. Typical laser materials include ruby crystal, Nd-doped yttrium aluminum garnet and semiconductor laser materials, which are essential and important materials for laser weapons.
New material is a pillar technology to meet the production demand of military equipment, and plays an important role in improving the performance of weapons and equipment and the combat effectiveness of the army. New material technology is widely used in the military, which can be upgraded and greatly improved when used in weapons and equipment. With the in-depth development of new materials and technology, the face of future weapons and equipment will change with each passing day.