Modification of Johnson-Cook Constitutive Equation and Stamping Finite Element Simulation of AM60 Magnesium Alloy

Gleeble-3500 thermal simulator was used to perform a hot tensile test on AM60 magnesium alloy plate, and the thermal deformation behavior of the magnesium alloy under deformation temperatures of 200-350 ℃ and strain rates of 0.01-0.1 s^-1 was studied. The strain hardening part of the Johnson-Cook equation was corrected and the coupling effect of strain rate and deformation temperature was considered; the modified Johnson-Cook constitutive equation was established with the hot tesile test data. The stamping finite element simulation was carried out by the equation, and the simulation was verified by tests. The results show that the rheological stress of AM60 magnesium alloy was positively correlated with the strain rate and negatively correlated with the deformation temperature. The stamping true stress-true strain curve of AM60 magnesium alloy predicted by the modified Johnson-Cook constitutive model was in good agreement with the test results, and the maximum relative error was 18.28%, which was 57.61% lower than that by the unmodified model. The barrel parts stamped at 200-350 ℃ were well formed and had no surface defects by simulation, which was consistent with the test results.