Strain rate effects on the mechanical properties of a Fe-Mn-Al alloy under dynamic impact deformations

We studied the mechanical properties of a Fe-Mn-Al alloy under dynamic impact tests at various strain rates in a split Hopkinson bar tester. The composition of the alloy is Fe-32 wt.% Mn-10 wt.% Al-1.07 wt.% C-0.36 wt.% Mo. After the impact tests, we employed the Zerilli-Armstrong constitutional equations to describe the behavior of deformation of the Fe-Mn-Al alloy under the impacts at high-stain rates. The deformation behaviors of the Fe-Mn-Al alloy were influenced strongly by the impacts at high strain rates. Both plastic flow stress and yield strength of the tested material increased and the corresponding strain decreased when the strain rates of the impact tests increased. The strain rate sensitivity increased, but the thermal activation volume decreased as the strain rate increased. Alloy strengthening was evident as the strain rate increased. Having put the measured parameters into the Zerilli-Armstrong equation, we could accurately predict the stress-strain curves of the Fe-Mn-Al alloy under the impacts at high strain rates. These results can be applied to engineering designs and for simulation purposes. (C) 2004 Elsevier B.V. All rights reserved.