Modeling and application of constitutive model considering the compensation of strain during hot deformation

Abstract

Hot compression tests were conducted on homogenized 5052 aluminum and AZ31 magnesium alloys to establish a strain compensated Arrhenius constitutive model in the temperature range of 573–723 K and 523–673 K with strain rates of 0.001, 0.01, 0.1 and 1 s−1 by using a Gleeble-1500D thermo-simulator. The presented constitutive model, as well as the dynamic recrystallization (DRX) kinetics of both studied alloys, was incorporated into ABAQUS User Subroutine UHARD to provide an effective means to study hot deformation. The simulated results were subsequently referred to the cellular automaton (CA) method to simulate the microstructural evolution of the 5052 and AZ31 alloys. Results show that the constitutive model considering strain compensation offers a high accuracy. In terms of force and volume fraction of DRX, the results of the Finite Element Method (FEM) are in good agreement with the experimental results. The microstructural evolution of both homogenized 5052 and AZ31 alloys during hot compression was simulated using CA coupled the FEM results. Owing to the close connection between dislocation density and flow stress, the alloys present similar characteristics with prolonged simulation time. The mean grain sizes of both studied alloys decrease with increasing strain, revealing that a large deformation degree leads to refined grains. The mean re-grain size initially peaks and then decreases smoothly with increasing strain because of the coupled effect the nucleation and growth of re-grains.