Hot Deformation Behavior and Processing Map of Cu-Cr-Nb-Zr Alloy

Hot compression tests were performed in the temperature and strain rate range of 700-900 °C and 0.001-10 s−1, respectively, to study the hot deformation behavior and further generate the constitutive equation and a processing map of the Cu-Cr-Nb-Zr alloy. The apparent activation energy for hot deformation was determined as 404±17 kJ mol−1 using Arrhenius type hyperbolic-sine equation. Possible reason for high activation energy was analyzed and the active deformation mechanism during hot deformation was further suggested. Constitutive equation was formulated to predict the flow stress. Dynamic material model was employed to generate the processing map and it was correlated with microstructural examination of the hot compressed specimens. Based on the microstructural observations, the optimum safe hot working parameters for Cu-Cr-Nb-Zr alloy were identified as 880-900°C/10-2 to 100.5 s-1 and 800-875 °C/100.5-101 s−1. The hot working parameters in the safe region were applied to the forging process and results agreed well with the processing map.