Hot deformation behavior and constitutive equation of a new type Al-Zn-Mg-Er-Zr alloy during isothermal compression

Isothermal compression tests of a new type Al-Zn-Mg-Er-Zr alloy are carried out on a Gleeble-3800 thermal simulator at temperatures varying from 300 to 460 degrees C and strain rates ranging from 0.001 to 10 s(-1). A comprehensive and scientific constitutive models based on the Arrhenius type equation have been developed from the experimentally measured data. The deformation temperature and strain rate have significant effect on flow stress and the material constants, such as alpha, beta, n, In A and Q are the functions of the strain. The flow stress calculated by the developed constitutive equation shows a close agreement with the experimental value, which indicates that the proposed constitutive equation can precisely analyze the hot deformation behavior of the Al-Zn-Mg-Er-Zr alloy. Due to the presence of coherent L1(2)-structured Al-3(Er,Zr) precipitates, the dominant softening mechanism is dynamic recovery during isothermal compression. (C) 2015 Elsevier B.V. All rights reserved.