Effects of particulate reinforcement and strain‐rates on deformation and fracture behavior of Aluminum 6061‐T6 under high velocity impact

Aluminum matrix composites (AMC) exhibit an attractive combination of mechanical and physical properties such as high stiffness and low density, which favors their utilization in many structural applications. Thus, increasing the structural applications of AMC is the driving force for the need to adequately understand their deformation and failure mechanisms under various types of loading conditions. In this study, plastic deformation of alumina particle reinforced Aluminum 6061‐T6 matrix composite is investigated and compared to that of an un‐reinforced Aluminum 6061‐T6 alloy at high strain‐rates under compressive loading. Dynamic stress‐strain curves are obtained using direct impact Split Hopkinson Pressure Bar (SHPB). Particulate reinforcement increases the deformation resistance of the aluminum alloy at high strain‐rates. Strain localization along narrow adiabatic shear bands is observed in both the reinforced and un‐reinforced alloy. Whereas the microstructure of shear bands in un‐reinforced alloy showed finer grain size compared to that of the bulk material, the shear bands observed in the AMCs are darker than the bulk material and the reinforcing particles are observed to be more closely spaced along the shear bands.