Constitutive Behavior And Processing Map Of As-Cast Mg-8y-6gd-1nd-0.17zn Magnesium Alloy Compressed At Elevated Temperatures

The constitutive behavior and hot workability of as-cast Mg-8Y-6Gd-1Nd-0.17Zn magnesium alloy during the hot compression were investigated at elevated temperature (350 similar to 450 degrees C) and different strain rates (0.0001 similar to 0.1 s(-1)) under the ultimate compression ratio of 50%. The relationship among these deformation parameters of Mg-8Y-6Gd-1Nd-0.17Zn alloy was characterized by a sine hyperbolic equation. The experimental results show that both temperature and strain rate have important effects on the flow stress behavior of Mg-8Y-6Gd-1Nd-0.17Zn magnesium alloy, and the flow stress increases at lower temperature and higher strain rates. Typical dynamic recrystallization character is found in the true stress-strain curves when samples are compressed at the temperature above 400 degrees C. The activation energy (Q) and stress exponent (n) during deformation are 359.258 kJ/mol and 5.24, respectively. The average error (ARE) between experimental and calculated values is 3.37%. Then, the processing maps are also established and analyzed based on dynamic material model. Considering the processing maps and microstructure observation, the optimum hot-working parameters of the alloy are determined to be temperatures of 400 similar to 450 degrees C and strain rates of 0.0001 similar to 0.001 s(-1).