Numerical Simulation of Microstructure Evolution and Mechanical Behavior of Medium-Mn Steel During Uniaxial Tension

Based on the microstructure obtained by test, the representative volume element(RVE) model of 7Mn steel was established. The microstructure evolution, stress and strain distribution during uniaxial tension of 7 Mn steel after warm rolling and annealing at different temperatures(600-630 ℃) was simulated by ABAQUS software and compared with the test results. The results show that when residual austenite was distributed along the tensile direction, it was tended to occur collaborative deformation to alleviate the strain concentration in ferrite and make the system in a high stress state. After annealing at 600 ℃, the residual austenite had high stability, and only part of austenite transformed into martensite at the end of uniform plastic deformation. The residual austenite almost transformed into martensite during tension after annealing at 630 ℃. The simulated residual austenite content was in good agreement with the test results and the relative error was less than 5%, verifing the accuracy of simulating microstructure evolution by RVE model. The simulated stress-strain curves after annealed at 615,630 ℃ were in good agreement with test results, and the relative error was less than 5%, verifing the accuracy of simulating uniaxial tensile behavior by RVE model. There was a large deviation between the simulation and the test results after annealed at 600 ℃ because of ignoring the refinement strengthening and solution strengthening in each phase constitutive model.