Hot tensile deformation behavior and constitutive model of ZK61M high-strength magnesium alloy sheet

Hot deformation behavior of the annealed ZK61M magnesium alloy sheet was explored using tensile tests with strain rates varying from 0.001 to 0.030 s(-1) in temperatures range of 423-513 K. The obtained results indicate that the flow stress increased with deformation temperature decreasing and strain rate increasing. Dynamic recrystallization (DRX) occurs when the temperature is higher than 423 K, and the recrystallization volume fraction increases with temperature rising. At a given temperature, the measured DRX volume fraction at a higher strain rate is smaller than that at a lower strain rate. Dimples are observed throughout the tested temperature range. Moreover, they grow larger as temperature increases. An average absolute relative error (AARE) of 2.65% proves that the peak stress predicted by the constitutive model is in good agreement with the experimental results. The correlation coefficient (R') obtained for the predicted stress and the experimental value considering the strain on the material constant are between 0.9831 and 0.9977. In addition, AARE and root mean square error (RMSE) are less than 6.5% and 8.5 MPa, respectively. This indicates that the deviation of the predicted value from the experimental value is small and the predictions of the proposed model are reliable. Graphic abstract

Automated summary

The hot deformation behavior of the annealed ZK61M magnesium alloy sheet was studied through tensile tests, indicating that the flow stress increased with lower deformation temperature and higher strain rate, with dynamic recrystallization occurring at temperatures higher than 423 K. The results show good agreement between the predicted peak stress from the constitutive model and the experimental values.