Microstructure based modeling of the strain rate history effect in wear resistant Hadfield steels

The strain rate history dependency of Hadfield steel is investigated by numerical modeling. A crystal plasticity model is employed to study the effect of strain rate jump/drop on the material's strain hardening and twinning propensity. Single crystal orientations are first examined to assess the importance of the strain rate and its history effects. Then a representative 3D microstructure aggregate is used to investigate the effects of strain rate history in a polycrystalline structure. It was found that strain rate affects the evolution of deformation twins in the microstructure, generating a strain rate history dependent deformation and hardening response. A Hadfield steel used in mineral crushing conditions is also characterized to provide details of the deformation and hardening behavior of the material under realistic low/high strain rate loading conditions. The importance of strain rate changes to strengthening and increasing the hardness of the polycrystal microstructure is discussed and considered from the wear resistance point of view.