A comparative study on mechanical and ballistic performance of functionally graded Al6061 composites reinforced with B4C, SiC, and Al2O3

Abstract

In the present study, functionally graded Al6061 composites reinforced with boron carbide (B4C), silicon carbide (SiC), and alumina (Al2O3) were prepared using the stir and centrifugal casting techniques. Arc-shaped functionally graded metal (FGM) specimens were treated with a hot-rolling process to enhance their mechanical properties and obtain laminated plates. Then, the impacts of ceramic reinforcements on the density, microhardness, tensile strength, and ballistic resistance of FGMs were studied. Moreover, the microstructural properties of the specimens were analyzed to elucidate the particle gradient from the inner to the outer surface. As a result, the microstructure observations revealed that the ceramic particles are dispersed from the inner to the outer periphery of the FGMs with centrifugal acceleration. A more homogeneous particle distribution was obtained in B4C-reinforced FGM compared to those of SiC and Al2O3. The hot-rolled FGM specimen reinforced with B4C offered the lowest density. The microhardness was improved by 32% and 30.4% in the inner to outer regions of the SiC- and Al2O3-reinforced FGMs, respectively, while it was improved by 22.6% in B4C-reinforced FGM. On the other hand, the tensile strength and elongation of the B4C-reinforced FGM specimen were better than those of the SiC- and Al2O3-reinforced FGMs. In addition, the highest ballistic protection was achieved with B4C-reinforced laminated FGM at an impact speed of 664.25 m/s with a penetration depth of 14 mm, while the impact speeds of SiC- and Al2O3-reinforced FGMs were 500.88 and 435.23 m/s, respectively.

Keywords

• FGMs
• Ceramic reinforcements
• Mechanical performance
• Ballistic behaviors
• Fracture