Multi-Scale Modeling of the Impact Response of a Strain-Rate Sensitive High-Manganese Austenitic Steel

Abstract

A multi-scale modeling approach was applied to predict the impact response of a strain rate sensitive high-manganese austenitic steel. The roles of texture, geometry, and strain rate sensitivity were successfully taken into account all at once by coupling crystal plasticity and finite element (FE) analysis. Specifically, crystal plasticity was utilized to obtain the multi-axial flow rule at different strain rates based on the experimental deformation response under uniaxial tensile loading. The equivalent stress-equivalent strain response was then incorporated into the FE model for the sake of a more representative hardening rule under impact loading. The current results demonstrate that reliable predictions can be obtained by proper coupling of crystal plasticity and FE analysis even if the experimental flow rule of the material is acquired under uniaxial loading and at moderate strain rates that are significantly slower than those attained during impact loading. Furthermore, the current findings also demonstrate the need for an experiment-based multi-scale modeling approach for the sake of reliable predictions of the impact response.

Micromechanical modeling of polycrystalline high manganese austenitic steel subjected to abrasive contact

“…The numerical results show that these are to be considered as microtwins because the local twin volume fraction is not high, but the twins have nucleated. One important aspect is that the hardening effect of microtwins is to be considered remarkable [10,47] because of the dense spacing of thin twin bands, that are dynamically growing barriers for dislocations. In addition, the number of active twin systems is high from 3 to 6 usually, making it more probable that they can act as non-coplanar barriers for dislocations and other twin systems.…”

“…The twin boundaries act as effective barriers against dislocations, cause dislocation pile-ups, and reduce the mean free path of the dislocations, effectively hardening the material. There are other contributors to the excellent strain hardening capability, such as the formation of dislocation walls [6,7] and dynamic strain aging (DSA) of Mn-C couples [8][9][10]. Furthermore, the material is strain-ratedependent due to the face-centered cubic (FCC) crystal structure.…”

“…Canadinc et al [7,21] have focused their efforts on numerically studying the effects of nitrogen and aluminum alloying in the material, to seek alternative compositions for improved mechanical behavior. Impact-related experimental study of Toker et al [22] and Gumus et al [23,24], and numerical modeling of Onal et al [10] have revealed that strong strain hardening of the Hadfield material is caused by the formation of nano-twins and their interaction with gliding dislocations, with a marked dependency on temperature and strain rate. The crystal plasticity simulations of Lindroos et al [25] have provided some insight into the behavior of Hadfield steel polycrystal microstructures under impact loading and its influence on wear behavior.…”