Dynamic Deformation Behavior of Dual Phase Ferritic-Martensitic Steel at Strain Rates From 10−4 to 2000 s−1

The deformation behavior of the dual phase steel (DP 1000 steel) was studied by the quasi-static tensile experiment and the dynamic tensile experiment. The experiments were carried out at strain rates ranging from 10−4 to 2000 s−1 at room temperature. Then the stress-strain curves of DP1000 steel in the strain rate range of 10−4–2000 s−1 were measured. By introducing the strain rate sensitivity factor m, Zerilli-Armstrong model was optimized. The constitutive equation parameters which formulate the mechanical behavior of DP1000 steel were fitted based on the Johnson-Cook (JC) constitutive model and the optimized Zerilli-Armstrong (ZA) constitutive model, respectively. By comparing indicators of “accuracy-of-fit”, R2 terms, for the two models, the optimized Zerilli-Armstrong constitutive model can reflect plastic deformation behavior both at the low and high strain rates more accurately. The reasons why the optimized Zerilli-Armstrong constitutive model is more advantageous than the Johnson-Cook model were discussed by using the yield strength and ultimate tensile strength (UTS) versus strain rates, and strain hardening rate versus effective plastic strain analytical methods.