The general trend of armor materials manufactured by manufacturers is to be stronger, lighter, more versatile and more efficient. Alumina ceramic material is an important branch of bulletproof material, which has high hardness and wear resistance, high compression strength and excellent ballistic performance under high stress.
There is a great difference between the bulletproof mechanism of alumina ceramics and metals. The metal absorbs the kinetic energy of the projectile because of plastic deformation, while the ceramic absorbs the kinetic energy of the projectile because of its fracture. Typically, a ceramic armor system consists of a monolithic ceramic or ceramic-metal composite covered with a layer of nylon cloth with a high tensile strength organic fiber binding.
Under the impact of the bullet, the alumina ceramic is broken on the front, while the remaining energy is absorbed by the reverse soft reinforcement material, which must be able to support the ceramic fragments and the bullet itself. As bulletproof ceramic requirements of performance more, of course, includes the density and porosity, hardness, fracture toughness, mechanical strength, young's modulus, sound, etc., any performance is not relation with overall bulletproof performance has a direct and decisive, and fracture mechanism is very complex, crack formation is caused by many factors, and the time is very short.
The porosity of alumina bulletproof ceramics should be as low as possible to improve the hardness and Young's modulus. And it has to be harder than a flying warhead; The speed of sound propagation in alumina ceramics indicates the ability of energy consumption on the impact surface of ceramics, and the high sound velocity indirectly indicates that ceramics have good densification and low closed pores.
Existing bulletproof ceramics are mainly divided into two categories, namely monolithic ceramics structure and ceramic composite structure. Monolithic ceramics include oxide ceramics and non-oxide ceramics, and binary systems. In general, non-oxide ceramics have higher physical properties and relatively low density, and are more advantageous as bulletproof than alumina ceramics. However, these materials manufacturing methods more expensive hot pressing, not easy to industrialization. But thermal pressure can improve the mechanical properties of bulletproof ceramics.
Moreover, ceramic matrix composites have high bullet-proof properties due to their high mechanical properties, especially fracture toughness. After projectile impact, ceramic-based composites have better integrity than monolithic ceramics. So alumina ceramics are very suitable for bullet-proof ceramics.