Possibilities and Principles of Formation of Functionally Graded Ceramic Armor by Additive Manufacturing.

Ceramic armor with improved ballistic performance, lower weight, and, in specific cases, complex geometry is of high importance for the armor integrators and users. The combination of a high level of consolidation and the tailored heterogeneous structures of these ceramics may be important for reducing fracturing and delaying crack propagation under high-velocity ballistic impacts, therefore improving their ballistic performance. This can be attained by a beneficial combination of advanced ceramic compositions and processing, e.g., through an additive manufacturing (AM) approach. For example, the functionally graded (FG) monolithic ceramic armor obtained by AM can encompass a few layers, where the front layer has higher hardness, and the layer(s) behind may have higher fracture toughness. The ingredients reinforcing the ceramic structure may also be involved. The graded architecture should provide the internal stress reduction under high-velocity mechanical (ballistic) impacts. The reaction bonding that provides consolidation of the AM-based ceramic armor may also be involved. The considered principles of the FG materials' formation may be employed for personnel, vehicular, and structural armor systems. The possibility of formation of ceramic armor with graded structures and compositions using AM was reviewed and analyzed for the first time. The proposed armor designs, which can be obtained by AM, may provide enhanced ballistic performance combined with lower weight.