![]() ![]() In addition, T74 target material was perforated completely, however, bullet stopped inside the target material at T6 condition resulted in localized material softening effect subsequent to the formation of ASB. Moreover, modification in microstructure and hardness of aluminum alloy target was observed within 2 mm distance from the crater hole. These hard metastable intermetallic compounds increase the hardness (above 654 HV) in some effected zones (deformed channels) because of reaction between the bullet particles and target aluminum alloy. ![]() Among interesting results, hard metastable intermetallic compounds (Al12W, Al3Ni2, Cu0.4W0.6) and pores were observed after ballistic impact. The effect of ballistic impact on structure and morphology of aluminum alloy substrate was investigated through optical microscopy (OM), scanning electron microscopy (SEM) and x-ray diffraction (XRD). The ballistic behaviour of single layered spray formed 7055 aluminum alloy was investigated under two different heat treatment (T6 & T74) against deformable 6 mm tungsten alloy (W-Ni-Fe) core projectile impact (1250 m/s). The results show that the ceramic nose has a great effect on the protection of bullet core.ĪA7055 aluminum alloy is being widely used in aerospace and aircraft industry. Based on the simulated results, the penetration performance was further analyzed in terms of the residual mass of bullet core. A numerical simulation was built and computed by ANSYS/LS-DYNA. The aperture and depth of perforation of projectile into the armor plates as well as the residual mass of bullet core under the same conditions were comparatively analyzed. According to impact dynamics theory, the performances of 30 mm ceramic-nose projectile and 30 mm standard projectile penetrating into the ceramic/A3 steel composite targets were analyzed and compared using DOP method, especially focusing on the effects made by different nose structures and materials. In order to improve the penetration of projectiles into ceramic composite armors, the nose of 30 mm standard projectile was replaced by a toughened ceramic nose, and the performance of ceramic-nose projectiles penetrating into ceramic/A3 steel composite targets has been experimentally researched. This study paves the way for future studies to further understand the influence of steel hardness on the ballistics performance of steel-encapsulated silicon carbide (SiC) armour modules. Results showed that increasing hardness of the backing enhanced the performance of the module while cover plate hardness had no influence within the range of hardnesses tested. The Johnson Cook model was applied in simulation of the steel confinement, accounting for the influence of hardness on JC model parameters. Hydrocode simulation of the experiments using LS-DYNA was carried out to model the penetration and failure processes that occurred in the armour modules. The different modes of failure of the backing plate and its influence on ballistic performance of the module were verified through visual inspection of test modules and analysis of high speed videos. Failure analysis of the armour modules and the measurement of residual penetration in the witness blocks were applied to characterize ballistic performance of the ceramic armour modules. A witness block of AISI 4340 steel was placed behind the armour module to capture the residual projectile. The armour modules were subjected to normal impact by conical tungsten alloy long rods of 8.3mm diameter and 115mm length, at a nominal striking velocity of 1.25 km/s. The armour module design composed of a SiC tile in confinement within 10 mm backing and 5 mm cover plates, which were made of AISI 4340 steel with varying hardnesses between HRC 30 to 50. An experimental study and hydrocode simulation was conducted to investigate the correlation between hardness of steel and the ballistic performance of steel-encapsulated SiC armour modules against long rod impact.
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