Constitutive modeling of hot deformation behavior of H62 brass

The hot deformation behaviors of H62 brass are investigated by isothermal compression tests on a Gleeble 1500 thermal-mechanics simulator in the temperature range of 650-800 degrees C and the strain rate range of 0.01-10 s(-1). Most of the stress-strain curves exhibit a single peak stress, indicating a typical dynamic recrystallization (DRX) behavior of the alloy. Further microstructural observation confirms the occurrence of DRX behavior and the beta ->alpha phase transformation of H62 brass under the deformation conditions. A new constitutive equation coupling flow stress with strain, strain rate and deformation temperature is developed on the basis of the Arrhenius-type equation, in which the Zener-Hollomon parameter is modified by considering the compensation of the strain rate. In the constitutive equation, the material constants alpha, n, Q and A are found to be functions of the strain. The flow stress predicted by the constitutive equation shows good agreement with the experimental stress, which validates the efficiency of the constitutive equation in describing the deformation behavior of the material. (C) 2011 Elsevier B.V. All rights reserved.