Ballistic performance of multi-metal systems

Ballistic resistance enhancement of armours and structures has been a prominent area of research over the years. Monolithic metallic plates have been the preferred choice for armours against high-velocity projectiles. High-strength steel is a popular choice for such systems. However, the high areal density deters in accommodating such systems in practical applications which require lightweight products. On the contrary, multi-metallic systems produced by the combination of low-density materials with similar or superior ballistic resistance as their monolithic counterparts have become attractive candidates in defence applications. However, only a limited number of comprehensive studies on the ballistic performance of multi-metal multi-layered targets are available in the literature. Moreover, these studies have drawn contradictory conclusions on the optimum arrangement of different layers and materials within the systems. In addition, existing knowledge in this area is scattered in the literature and there is a need to collate them to enhance the development of multi-metal multi-layered ballistic-resistant plate systems in order to be optimised for ballistic-related armour. This article aims to provide a comprehensive review of the effect of different metals, thickness, fracture mechanisms, feasibility of the connection types and the order of the metallic plates within targets on the ballistic performance.