High-temperature Flow Stress Behavior of Continuous Extrusion Copper Bus Bar
The flow stress of continuous extrusion copper bus bar was investigated at 300-700 ℃ and strain rate 0.01-1.0 s-1 on Gleeble1500 test machine.The results show that the flow stress curve shows obvious steady flow curve feature below 500 ℃,and it is a typical single-peak dynamic softening curve;the steady flow curve characteristic is not obvious above 500 ℃,the material is difficult to enter steady flow state.The higher the deformation temperature or the lower the strain rate,the more obvious the dynamic softening curve feature.During high temperature deformation,the flow stress of copper bus bar can be represented by Zener-Hollomon parameter in the hyperbolic sine equation.The hot deformation activation energy Q of the material is 205.445 kJ/mol,Z equation is Z=exp(205.445/ RT).