Study on Dynamic Mechanical Behaviors and J–C Constitutive Model of a Fine-Grained D6A Steel

The uniaxial tensile loading tests of coarse-grained D6A steel (CG, d = 20 ?m) and fine-grained (FG, 1.5 were performed using a material testing machine rotating disk Hopkinson tension bar, respectively. stress–strain curves two steels at different strain rates (0.001~1500 s?1) obtained. Results show that grain refinement effectively improves the strength FG steel, which is achieved by high-density boundaries cementite particles hindering movement dislocations. In rate range test, sensitivity decreases, considered to be result athermal stress independent becomes dominant part total stress. Combined with experimental data, parameters Johnson–Cook (J–C) constitutive model calibrated. obtained simulations are in good agreement those from tests. These results may provide an important reference theoretical basis for application various fields.