A quantitative insight into strain hardening behavior of typical Hadfield steel under dynamic load

Abstract

In this paper, the critical threshold associated to the activating of strain hardening capacity with respect to typical Hadfield steel Mn13Cr2 was explored quantitatively utilizing a Separated Hopkinson Press Bar (SHPB). The strain hardening behavior of the Mn13Cr2 under dynamic load was investigated, systematically, and the strain hardening mechanisms involved in different plastic deformation conditions were illuminated. Results indicated the overall plastic deformation process under different dynamic loads could be divided into three stages, including the (LHS), the (HHS) as well as the parabolic hardening stage (PHS). The critical transformation strength (CTS) from LHS to the HHS showed a trend of increasing first and then decreasing with the shock pressure increasing from 0.1 MPa to 0.8 MPa, and the maximum hardening effect with respect to the studied Mn13Cr2 steel could be activated at dynamic load threshold of 0.6 MPa with max CTS of ∼493.6 MPa. Dislocation-dominated strengthening mechanism and C–Mn atomic dipoles strengthening mechanism induced by dynamic strain aging were responsible for the excellent strain hardening capability when the impact load was increased above 0.6 MPa.