Dynamic deformation behavior of ultrafine-grained iron produced by ultrahigh strain deformation and annealing

The dynamic tensile deformation behavior of ultrafine-grained interstitial free steel is shown in this paper. As the strain rate increased, the yield drop phenomenon became more significant in the stress–strain curves. The difference in flow stress between the dynamic and quasi-static strain rates did not decrease with grain refinement, in contrast to conventional high-strength steels. It is suggested that the grain refinement affected mainly the athermal component of the flow stress.

Research highlights
► Dynamic tensile deformation behavior of ultrafine grained interstitial free steel is shown. As strain rate increased, yield drop became more significant in stress-strain curves. The strain rate dependence of flow stress kept as high value as that in mild steel. The grain refinement seemed to affect mainly the athermal component of the flow stress.