不同撞击速度下穿燃弹侵彻陶瓷/铝合金复合靶板时弹芯破碎失效特性研究

为了研究12.7 mm穿燃弹以不同速度撞击陶瓷/铝合金复合靶板时弹芯的破碎及失效特性，开展了12.7 mm穿燃弹以434.5～844.6 m/s速度撞击SiC陶瓷/6061T6铝合金复合靶板的弹道试验，分析了弹靶的失效模式。弹芯在侵彻靶板后会产生不同尺寸的碎片，使用回收箱收集弹芯碎片并用不同孔径筛网对其进行筛分、称重，得到了不同撞击速度下弹芯碎片的质量分布，并对不同部位的弹芯碎片断口形貌进行了宏观和微观观测分析。研究结果表明:背板失效模式为碟形变形-剪切穿孔-花瓣形失效，试验后的弹芯碎片累积质量分布符合Rosin-Rammler幂率分布规律，且随着着靶速度的增大，小质量碎片质量增加；弹芯在冲击过程中等效直径较大碎片（大于8 mm）失效模式为拉伸脆性断裂，而等效直径小于2 mm的碎片上存在局部塑性剪切断裂。

Dynamic fragmentation and failure of the hard core of a 12.7 mm API projectile against SiC/6061T6Al composite armor with various impact velocities

The high hardness combined with its lower density makes silicon carbide (SiC) an attractive candidate for armor material. The main purpose of employing ceramics plate is to erode and fragment the impacting projectile, such as a 12.7 mm armor piercing incendiary (API) projectile with a very hard steel core. To explore the failure mechanism of the hard steel core, the ballistic impact experiments were carried out to study the dynamic responses of 12.7 mm API projectiles impacting ceramic/aluminium alloy composite armors. The SiC ceramics/6061T6 aluminium alloy composite targets with the composite cover on the front of the SiC were tested at speeds of 434.5, 503.1, 662.7, 704.6 and 844.6 m/s. The targets were entirely perforated by 12.7 mm API projectiles with the hard steel cores. The damages of projectiles, ceramic and back plates were analyzed phenomenologically. The damage modes of ceramic and steel backplates were identified. The resulting core fragments were collected and separated through a series of sized sieving screens, which allowing the core fragmentation to be quantified. The cumulative mass distribution curves of core after impact under various velocities were obtained. Microstructural and mechanical responses to the ballistic impacts were studied by using scanning electron microscope (SEM), showing that the core was broken into different particle sizes under the action of stress wave and impact. The cumulative mass of the steel core conforms to the Rosin–Rammler power function distribution. With the increase of impact velocity, both the power index k and the average characteristic size λ decreased. Average characteristic size λ can be used to characterize the fragmentation degree of the whole core to a certain extent. The failure mode of the larger equivalent diameter fragment (greater than 8 mm) in the process of impact was a tensile brittle fracture, while the local plastic shear fracture existed on the fragments with an equivalent diameter less than 2 mm.