Study On The Damage Behavior Of Two-Phase Titanium Alloy Projectiles

In this paper,the damage behavior of two-phase titanium alloy targets under projectile penetration is studied.The experimental materials used two-phase titanium alloys with different structures and properties.The projectiles were selected from armor-piercing firearms and armor-piercing bombs that diameters were 7.62 mm,12.7mm and 14.5mm.Using optical microscopy,metallographic microscopy,and scanning electron microscopy,the adiabatic shear bands and deformation structures near the crater were observed.The hardness change near the crater was tested using Vickers hardness,and the microscopic damage characteristics of the target,distribution characteristics and regularity of shear bands were obtained,and the damage zone inside the titanium alloy target was characterized by ultrasonic C scan,X-ray inspection and industrial CT system.The research results show that the three kinds of titanium alloys(thickness 40mm)studied in this paper all have the ability to protect 7.62 mm and 12.7mm caliber projectiles.Among them,2# and 3# have the ability to prevent the penetration of projectiles with 14.5mm caliber.The improvement of the hardness will help improve the protection ability.After the hardness reaches a certain value,it will have a stronger protective ability.The macroscopic appearance of the impact pits show that the ope n pit area is formed by the adiabatic melting and splashing of protective material under the action of high-energy rapid impact and the embrittlement of the material under high-speed action,and the penetrating zone is formed by the high-speed deformation of the protective material caused by high-speed extrusion of the projectile.The titanium alloy studied in this article is mainly made of embrittlement,crushing and splashing under the action of armor-piercing incendiary bombs.The impact energy absorption efficiency and the dissipation rate of the projectiles from different parts of different deformation tissues in the penetration zone are different for the projectile.The adiabatic shear zone is the main factor of the damage in the penetrating zone.The adiabatic shear band distribution in the two-phase titanium alloy is bimodal,and the two-phase titanium alloy is dominated by plastic deformation and energy absorption.The primary ?-phase + lamellar two-phase titanium alloys are mostly adiabatic shear bands with variable morphology,which mainly form energy in the form of cracks,and have better energy absorption.The macroscopic damage area can be distinguished by the hardness measurement of the metallographic anatomical section;Ultrasonic C-scan can effectively quantify the size of the crater,but the measurement size will be larger than the actual size,and the crack caused by internal damage around the crater can be found.Radiographic film imaging can effectively quantify the size of the crater.The effect of radiography on the density of the titanium alloy is less than the actual size.The high density of inclusions around the crater can be found.It is difficult to find cracks between layers due to the problem of cracks.The ray CT can accurately measure the size and shape of the crater,and can detect high-density inclusions,but the crack detection rate is low.The research results of this paper can be directly used in aircraft armor design and have high practical value.