The high strain rate deformation behaviour and dislocation substructure of AZ80 magnesium alloy are investigated at strain rates of 8x102 s-1, 1.5x103 s-1 and 2.2x103 s-1 and temperatures of-100 ºC, 25 ºC and 300 ºC using a compressive split-Hopkinson pressure bar system. The flow stress, work hardening coefficient, strain rate sensitivity and temperature sensitivity all increase with increasing strain rate or decreasing temperature. Moreover, the dynamic deformation behaviour is well described by the Zerilli-Armstrong hcp constitutive equation. Transmission electron microscopy observations show that the dislocation density increases with a higher strain rate or a lower temperature. Finally, the flow stress varies linearly with the square root of the dislocation density in accordance with the Bailey-Hirsch model.

The dynamic deformation behaviour and dislocation substructure of AZ80 magnesium alloy are investigated at strain rates of 8 × 102, 1.5 × 103 and 2.2 × 103 s−1 and temperatures of −100, 25 and 300°C using a compressive split-Hopkinson pressure bar system. The flow stress, work hardening coefficient, strain rate sensitivity and temperature sensitivity all increase with increasing strain rate or decreasing temperature. Moreover, the dynamic deformation behaviour is well described by the Zerilli–Armstrong hexagonal close packed (hcp) constitutive equation. Catastrophic failure occurs at all three temperatures under strain rates of 1.5 × 103 and 2.2 × 103 s−1. Transmission electron microscopy observations show that the dislocation density increases with a higher strain rate or a lower temperature. Finally, the flow stress varies linearly with the square root of the dislocation density in accordance with the Bailey–Hirsch model. This paper is part of a thematic issue on Light Alloys.