Strain-Compensated Arrhenius-Type Constitutive Model for Flow Behavior of Al-12Zn-2.4Mg-1.2Cu Alloy

The isothermal hot compression tests of as-extruded Al-12Zn-2.4Mg-1.2Cu alloy were performed on a Gleeble-3500 thermo-simulation machine. Based on the Arrhenius-type constitutive model, the experimental stress-strain data over a wide range of temperatures (523∼723 K), strains (0.1∼0.6) and strain rates (0.001, 0.01, 0.1 and 1 s−1) were employed to develop a suitable constitutive model to predict the elevated temperature flow behavior. The effects of temperature and strain rate on deformation behavior were represented by Zener-Holloman parameter in an exponent-type equation. The influence of strain was incorporated in constitutive analysis by considering the effect of strain on material constants. Suitability of the developed constitutive model was evaluated by comparing experimental and predicted data in terms of correlation coefficient (R) and average absolute relative error (AARE). Results show that the values of R and ARRE are 0.995 82 and 6.66%, respectively, which indicate that the developed model considering the compensation of stain can predict flow stress of experimental alloy and has good correlation and generalization.