Study on mechanical and ballistic performances of boron carbide reinforced Al 6061 aluminum alloy produced by powder metallurgy

In this study, the density, hardness, impact toughness, transverse rupture strength, tensile strength and ballistic resistance of Al 6061 alloy reinforced with boron carbide (B4C) powders were studied to elucidate the influence of the ceramic content and production process on the physical and ballistic properties of the resulting composites. Powder-metallurgy and hot-extrusion techniques were used to manufacture the Al 6061-based metal matrix composites reinforced with 5 wt%, 10 wt%, 15 wt% and 20 wt% B4C. The hot-rolling process was performed on a group of specimens to examine the effect on the mechanical and ballistic behaviors. The results revealed that a uniform particle distribution was achieved in a matrix structure and higher relative density values were measured in all specimens. The hardness, transverse rupture strength and tensile strength were improved and impact toughness was decreased with increasing volume fraction of B4C particle reinforcement for both hot-extruded and hot-rolled specimens. The highest flexural strength was measured in hot-extruded specimens and the maximum tensile strength was obtained in hot-rolled composites. The deformation tests showed that transgranular cracking occurred on B4C particles and particles were retained in the matrix. The hot-extruded, hot-rolled and laminated with two hot-rolled specimens were subjected to a ballistic test with a 7.62 mm × 51 mm M80 projectile for Type III and the ballistic resistance investigated by analyzing the hole surface in the armor. The hot-rolled and hot-extruded specimens were perforated in ballistic tests and exhibited ductile behavior with the petal failure mechanism. The two-layer hot-rolled specimens successfully absorbed the impact energy of the bullet with the lowest depth of penetration and smooth bulging.