Surface modification effects of ceramic tile on the impact resistance of ceramic tile/MMC composites

Abstract

Various ceramic materials like alumina $(Al_2O_3)$, silicon carbide (SiC), and boron carbide $(B_4C)$ have commonly been used for armor materials because they have good mechanical properties like high hardness, compressive strength, and low density. Among above ceramics, both SiC and $B_4C$ have competitive mechanical properties compared to other ceramic materials. Aluminum (Al) has been used for fabricating enhanced composite armor combined with ceramics due to its low density and high fracture toughness. If SiC or $B_4C$ and Al are combined, SiC/Al and $B_4C/Al$ composite can be applied to lightweight armor, because they can have improved impact resistance by combining mechanical properties of metal and ceramic. However, carbide/Al composites have weakness at their interface, originating from the detrimental reactions and poor wettability between carbide ceramics and Al. Therefore, many research have been attempted to improve interfacial adhesion between ceramic particles and Al matrix. Although there are many studies regarding the wettability and interfacial bond strength in ceramic particles reinforced Al matrix composites, but none of them focus on the bulk type of ceramic tile reinforced Al-alloy matrix composite. This study focuses on analyzing the effects of surface modification of SiC and $B_4C$ tiles on the wettability, interfacial adhesion, and impact resistance of ceramic tile/MMC (metal matrix composite) composites by liquid state fabrication. The effect of coating layers of $SiO_2$ , Ni, and Si on SiC and $B_4C$ surface on the microstructures and impact resistance were analyzed. The wettability and push-out tests were conducted to analyze the effect of surface modification of the SiC and $B_4C$ tiles on wetting be-havior with Al7075 alloy. The interfacial bond strength of the surface modified SiC/MMC and $B_4C/MMC$ composites was improved compared to that of the as-received one due to the suppression of the brittle $Al_4C_3$ formation at the interface between SiC/MMC and $B_4C/MMC$ composites. The drop-weight test was conducted to analyze impact resistance of SiC/MMC and $B_4C/MMC$ composites by different surface modification. The impact resistance of the surface modified SiC/MMC and $B_4C/MMC$ composites was also enhanced owing to their strong interfacial bond strength at the interface.