Characterization of hot deformation behavior of as-extruded Mg-Gd-Y-Zn-Zr alloy

The hot deformation characteristics of as-extruded Mg-Gd-Y-Zn-Zr alloy have been investigated by isothermal compression tests in the temperature range of 300-500 degrees C and strain rate range of 0.001-1 s(-1). Several modeling approaches, including flow stress-strain curves, a constitutive Arrhenius type equation model and processing map were used to characterize the deformation behavior of as-extruded Mg-Gd-Y-Zn-Zr alloy in this study. In addition, isothermal precision forging of the component with complex shape was carried out to evaluate the optimum parameters for hot working of the alloy at elevated temperatures. The results show that the deformation activation energy of the experimental alloy was estimated to be 240.477 kJ/mol, and the stress exponent was 3.899. The optimum parameters for hot working of the as-extruded Mg-Gd-Y-Zn-Zr alloy were deformation temperatures of 380-450 degrees C and strain rates of 0.003-0.02 s(-1). According to the determined hot deformation parameters, three components were successfully prepared, and its possessed excellent surface quality, the ultimate tensile strength, yield strength and elongation of the component were 378 MPa, 283 MPa and 11.5%, respectively. (C) 2014 Elsevier B.V. All rights reserved.