Hot Deformation Behavior and Constitutive Equation of Cu–Cr–Zr Rods Prepared by Upward Continuous Casting

Continuous extrusion is a very promising technique for forming Cu–Cr–Zr alloys which takes the upward continuous casted rods as raw materials. While the hot deformation behavior and constitutive equation of as-cast rods have never been reported. In the present study, the hot deformation behavior of as-cast Cu–Cr–Zr rods with columnar grains was investigated. The results showed that the flow stress at 500 °C is higher than that at 400 °C. The reason for that can be attributed to the dynamic precipitation process, which was confirmed by TEM observations. At this temperature, partial CDRX dominates the softening mechanism while at high temperatures DRV and DDRX play a critical role. The constitutive equation was then established and the deformation activation energy was determined to be 541.93 kJ/mol. The high activation energy was attributed to the large solidified columnar grains. At high strains, stable metal flows can be obtained at high strain rates and high temperatures according to the processing maps, which indicates that a high-speed deformation at a high temperature is favorable to the plastic forming of this material. This investigation thus provides valuable information on how to process the Cu–Cr–Zr rods by plastic deformation methods, for example, continuous extrusion.