Review of the application status and development trends of 16 major military new materials（2）

Military functional materials 1. Optoelectronic functional materials Optoelectronic functional materials refer to materials used in optoelectronic technology. They can transmit and process information combined with optoelectronics, and are an important part of modern information technology. Optoelectronic functional materials are widely used 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, hoods, and fairings for infrared detection systems of aircraft, missiles, and ground weapons and equipment. Magnesium fluoride has high transmittance, strong resistance to rain erosion and erosion, and is a good infrared transmission material. Laser crystals and laser glass are materials for high-power and high-energy solid lasers. Typical laser materials include ruby crystals, neodymium-doped yttrium aluminum garnets, semiconductor laser materials, etc. 2. Hydrogen storage materials Some transition cluster metals, alloys, and intermetallic compounds, due to their special lattice structure, hydrogen atoms can easily penetrate into the tetrahedral or octahedral interstitial sites of the metal lattice to form metal hydrides. This material is called a hydrogen storage material. In the weapons industry, lead-acid batteries used in tank vehicles need to be charged frequently due to their low capacity and high self-discharge rate, which makes maintenance and transportation very inconvenient. The discharge output power is easily affected by the battery life, charging state and temperature. In cold climates, the starting speed of tank vehicles will be significantly slowed down, or even unable to start, which will affect the combat capability of the tank. Hydrogen storage alloy batteries have the advantages of high energy density, overcharge resistance, shock resistance, good low temperature performance, and long life. They have broad application prospects in the development of main battle tank batteries in the future. 3. Damping and shock absorbing materials Damping refers to the phenomenon that even if a freely vibrating solid is completely isolated from the outside world, its mechanical properties will be converted into thermal energy. The purpose of using high damping functional materials is to reduce vibration and noise. Therefore, damping and shock absorbing materials are of great significance in the military industry. The application of foreign metal damping materials is mainly concentrated in industrial sectors such as ships, aviation, and aerospace. The US Navy has adopted Mn-Cu high damping alloy to manufacture submarine propellers, which has achieved significant shock absorption effects. In the West, the application research of damping materials and technologies in weapons has received great attention. Some developed countries have set up research institutions specifically for the application of damping materials in weapons and equipment. After the 1980s, foreign damping, shock absorption and noise reduction technology has made greater progress. With the help of the application of CAD/CAM in shock absorption and noise reduction technology, they integrated design-materials-processes-tests and carried out damping, shock absorption and noise reduction design of the overall structure. my country conducted research on damping, shock absorption and noise reduction materials around the 1970s and achieved certain results, but there is still a certain gap compared with developed countries. Damping materials are mainly used in the aerospace field to manufacture the shells of control panels or gyroscopes such as rockets, missiles, and jets; in the shipbuilding industry, damping materials are used to manufacture propellers, transmission components and cabin partitions, effectively reducing the vibration and noise generated by surface collisions during the meshing process of mechanical parts. In the weapons industry, the vibration of the tank transmission part (gearbox, transmission box) is a complex vibration with a wide frequency range. The application of high-performance damping zinc-aluminum alloy and vibration-damping wear-resistant surface deposition material technology has greatly reduced the vibration and noise generated by the transmission part of the main battle tank. 4. Stealth materials The development of modern attack weapons, especially the emergence of precision strike weapons, has greatly threatened the survivability of weapons and equipment. It is no longer practical to simply rely on strengthening the protection capabilities of weapons. The use of stealth technology can make the enemy's detection, guidance, and reconnaissance systems ineffective, so as to conceal oneself as much as possible and seize the initiative on the battlefield. Preemptively discovering and destroying the enemy has become an important development direction for modern weapon protection. The most effective means of stealth technology is to use stealth materials. Foreign research on stealth technology and materials began during the Second World War, originated in Germany, developed in the United States, and expanded to advanced countries such as Britain, France, and Russia. At present, the United States is at the leading level in the research of stealth technology and materials. In the field of aviation, many countries have successfully applied stealth technology to the stealth of aircraft; in terms of conventional weapons, the United States has also carried out a lot of work on the stealth of tanks and missiles, and has been used in equipment one after another. For example, the US M1A1 tank uses radar wave and infrared wave stealth materials, and the former Soviet Union T-80 tank is also coated with stealth materials. Stealth materials include millimeter wave structural absorbing materials, millimeter wave rubber absorbing materials and multifunctional absorbing coatings, which can not only reduce the probability of detection, tracking and hitting of millimeter wave radar and millimeter wave guidance systems, but also be compatible with the effects of visible light, near infrared camouflage and medium and far infrared thermal camouflage. In recent years, while improving and improving traditional stealth materials, foreign countries are committed to exploring a variety of new materials. Whisker materials, nanomaterials, ceramic materials, chiral materials, conductive polymer materials, etc. are gradually applied to radar wave and infrared stealth materials, making the coating thinner and lighter. Nanomaterials have excellent wave absorbing properties, wide bandwidth, good compatibility, and thin thickness. Developed countries have studied and developed nanomaterials as a new generation of stealth materials; the research on millimeter wave stealth materials in China started in the mid-1980s, and research units mainly focused on weapon systems. After years of hard work, pre-research work has made great progress. 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 fourth-generation supersonic fighter jets being developed in the world use composite materials, wing-body fusion and absorbing coatings for their fuselage structure, which makes them truly stealthy. Electromagnetic wave absorbing coatings and electromagnetic shielding coatings have begun to be painted on stealth aircraft; the surface-to-air missiles of the United States and Russia are using stealth materials with light weight, wide-band 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 in various countries in the world.

The development trend of new military materials in my country The new materials used in the military industry have high technical content, so the industrialization speed of new military materials is generally slow. New military materials around the world are developing in the direction of functionalization, ultra-high energy, composite lightweight and intelligentization. From this point of view, titanium alloys, composite materials and nanomaterials have very good industrialization prospects in the military industry. Titanium alloy Titanium is a metal with excellent performance and abundant resources developed in the 1950s. With the increasingly urgent demand for high-strength and low-density materials in the military industry, the industrialization process of titanium alloys has been significantly accelerated. In foreign countries, the weight of titanium materials on advanced aircraft has reached 30-35% of the total weight of the aircraft structure. During the "Ninth Five-Year Plan" period, in order to meet the needs of aviation, aerospace, ships and other departments, the country has made titanium alloy one of the development priorities of new materials. It is expected that the "Tenth Five-Year Plan" will become a period of rapid development of new materials and new processes for titanium alloys in my country.
The development of composite military high technology requires that materials are no longer single structural materials. Under this condition, my country has made great achievements in the research and application of advanced composite materials, and its development during the "Tenth Five-Year Plan" will be more eye-catching. The development direction of composite materials in the 21st century is low cost, high performance, multi-function and intelligent. Nanomaterials Nanotechnology is the product of the combination of modern science and technology. It not only involves all existing basic scientific and technological fields, but also has broad application prospects in the military industry. With the sudden increase in the suddenness of future wars, various detection methods are becoming more and more advanced. In order to meet the needs of modern warfare, stealth technology occupies a very important position in the military field. Nanomaterials have a high absorption rate of radar waves, thus providing a material basis for the development of weapon stealth technology.