High strain rate dynamic compressive behaviour of Al6061-T6 alloys

Abstract

This paper investigated the compression behaviour of Al 6061-T6 alloys at various high strain rates through split Hopkinson pressure bar (SHPB) experiments. The compressive strength (σc) of Al 6061-T6 alloy was measured in the present work as a function of high strain rate ε̇. The measurements were done in the strain rate regime of 3×103 to 6.5×103s−1. The results showed that the corresponding (σc) increased exponentially with increase in (ε̇). But, the increase in strain with increasing ε̇ was primarily linear. The work hardening coefficient decreased with the increase of strain. However, the decrease of work hardening coefficient with increasing strain rate did not follow a similar trend. With the increase of ε̇ the strain rate sensitivity increased. As expected, the thermal activation volume decreased with increase in ε̇. Using the Zerilli-Armstrong equation attempt was made to evaluate the related material constants to predict the stress-strain curves. The predicted stress-strain behaviours matched reasonably well with those measured experimentally in the current SHPB experiments. The implication of these results in engineering design and simulation in the context of resisting high strain rate impact was also discussed.