Dynamic mechanical properties of four aluminum alloy were attained with the split Hopkinson pressure bar (SHPB) apparatus. According to the characters of the stress-strain curves, the Cowper-Symonds constitutive model was chosen and its relationship parameters were fitted according to the experiment data. The failure modes and their dynamic mechanical properties were compared among the four materials. The results show that LF6R and LF21M have good plasticity, LY12CZ and LC4CS have some brittleness. The tangent modulus linearly increase with yield stress. Among the four experimented aluminum-alloy materials, the strain-rate sensitivity of LC4CS is minimum; the strain-rate sensitivity of LF6R is maximum; the strain-rate sensitivity curves of LF21M, LY12CZ and LC4CS have the same shape.
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