Influence of Using SiC and Al2O3 Ceramic Front Layer on Ballistic Performance of a Bainitic Steel: A Comparative Study

Development of lightweight armors is vital in order to provide ballistic protection in a more effective way. The weight of steel armor can be decreased significantly by setting a front ceramic layer on it. In this paper, the influence of utilizing SiC and Al₂O₃ ceramic front layer on the ballistic behavior of 4140 bainitic steel was investigated experimentally. All steel plates were initially subjected to the austempering treatment by applying the austenitization at 860 °C for 1 h and then holding in a salt bath at 343 °C for 50 min to get fully bainitic microstructure. And then, the laminated composites, consisting of SiC or Al₂O₃ front layer (50 × 50 mm in size) and bainitic steel backing layer, were prepared by joining these layers with an acrylic adhesive. After the mechanical and microstructural characterization of the bainitic steel, the ballistic shots were made using 7.62 × 51 mm AP projectile with an average speed of 788.4 m/s on both monolithic steel and layered armor samples for comparison. The samples, which stopped the bullet at normal impact condition without complete perforation or disintegration of the bainitic steel layer, were termed as successful. The bainitic steel achieved the ballistic protection at a thickness ≥ 14 mm but the use of SiC layer provided the weight saving of at least 42.9% and the Al₂O₃ front layer enabled the weight reduction of 28.6% in the armor with respect to the monolithic 4140 bainitic steel.