Solid solution induced back-stress in multi-principal element alloys: Experiment and modeling

The kinematic and isotropic hardening behavior was investigated for high and medium entropy alloys with a single-phase face-centered cubic (FCC) structure. The cross-slip associated with screw dislocations in FCC structures is strongly influenced by local fluctuations in the spatial distribution of different atom species. The local atomic arrangements inhibit the movement of Shockley partial dislocations during plastic deformation, thereby lowering the probability of cross-slip and generating a higher back-stress. This study used a solid-solution induced back-stress model, which combines nonlinear kinematic and isotropic hardening, to investigate the effects of dislocation forest stress and back-stress in a non-equiatomic Cr₁₂Fe₄₂Mn₂₄Ni₂₂ medium entropy alloy. Based on the experimental results, numerical simulations by the finite element method were performed to validate this modeling approach.