ABSTRACT
In the present work, gradient-grained Fe was synthesized by means of surface mechanical grinding treatment, and the compression behaviors of the coarse-grained Fe and the gradient-grained Fe were investigated under both quasi-static and dynamic loading conditions over a wide range of strain rates. The strain hardening behaviors and the observed flow stresses for resisting plastic deformation of metals and alloys also highly depend on the rate associated with loading. The microstructure after surface mechanical grinding treatment was examined by optical microscope, electron backscattered diffraction, transmission electron microscope and micro-hardness measurements. Dynamic compression tests were performed using Hopkinson-bar techniques. Details of the Hopkinson-bar technique and the data analysis for true stress, true strain and true strain rate can be found elsewhere. The strain hardening behaviors and strain rate sensitivity of the as-annealed Fe and the gradient-grained Fe under compression were then studied over a wide range of strain rates.
