Dynamic mechanical properties and comparison of two constitutive models for martensitic stainless steel 0Cr17Ni4Cu4Nb

The purpose of the study is to investigate the dynamic mechanical properties and constitutive relationship of martensitic stainless steel 0Cr17Ni4Cu4Nb. For this purpose, the impact test was performed at six strain rates (750, 1500, 2000, 2600, 3500, and 4500 s−1) and four temperatures (25, 350, 500, and 650 °C) by using the high-temperature split Hopkinson pressure bar (SHPB) test device to attain the stress–strain relationship of materials; in addition, quasi-static (0.001, 0.01, and 0.1 s−1) compression tests were conducted by applying the UTM5305 universal testing machine at normal temperature. The analysis of the stress–strain curves indicates that the stainless-steel shows strain-rate strengthening and thermal softening and the adiabatic temperature rise during the plastic deformation at a high strain rate exerts a thermal softening effect on materials. With the aid of Johnson-Cook (J-C) and power-law (P-L) constitutive models, the dynamic constitutive relation of the martensitic stainless steel 0Cr17Ni4Cu4Nb was fitted and the correlation coefficients (R) and average absolute relative errors (AAREs) obtained through use of the two constitutive models were compared. Results indicate that the curves obtained through the constitutive models match the test curves to a reasonable extent. The R values are 0.968 33 and 0.977 80 while AAREs obtained through the J-C and P-L models are 4.77% and 2.25%, respectively. It can be found that the P-L model is slightly superior to the J-C model in terms of fitting accuracy. In addition, the dynamic mechanical properties of the materials were assessed through use of their constitutive equations from the perspectives of strain-rate sensitivity and temperature sensitivity and the acquired results are relatively consistent with the test results.