Constitutive Relation And Thermal Flow Behavior Of Conductor Material Of Cu-Ag Binary Alloy

Contact wire is one of the most important part of the transmission system for the high-speed railway hanging in the air, and subject to the tensile stress and Joule heat. Cu-Ag alloys with good mechanical and electrical conductivity properties can offer sufficient benefits for the operating requirement of contact wire. The combination of strength and electrical conductivity for Cu-Ag alloys is affected by the hot pre-deformation process. However, there are few investigations about the hot deformation behavior for C u-Ag alloys, which result in the lack of theoretical guidance for the process. The isothermal compression tests and metallographic observations are applied to analyze the hot deformation feature and explore the mechanism of microstructure evolution of C u-6%Ag alloy based on the dynamic materials model. The main conclusions can be shown as following:(1) The microstructure evolution law and flow deformation feature of Cu-6%Ag alloy at high temperatures and strain rates. To obtain the true stress-strain curves, the compressive deformation behavior of C u-6%Ag alloy is investigated on the Thermecmastor-Z thermo- mechanical simulator. To explore the law of microstructure evolution of Cu-6%Ag al oy, the metallographic observations are applied.(2) Exploration for low strain instability and stress mutation of Cu-6%Ag alloy. To explore the microstructure evolution behavior and analyze the variation of stress-strain curves under different conditions, the power dissipation efficiency and instability t heory are quoted in the investigation. The mechanism of twinning and interior dynamic recrystallization are studied when the power dissipation efficiency reaches the maximum value.(3) Modification and establishment of DRV-DRX and simplified constitutive model. The DRV-DRX constitutive model was improved by the modification Avrami equation and Arrhenius model. To generalize the simplified constitutive model, which could be used to predict the stress of dynamic recovery curve, by quoting Z parameter.(4) The secondary development about the flow stress subroutine of DEFORM-3D. Three new FEM engine of DEFORM-3D embedding the models, DEF_SIM.exe, DEF_SIM_P4.exe and DEF_SIM_P4P.exe, are developed by using FORTRAN. The accuracy of the established models are vivificated by FEM based on the established engines.Based on those investigations, the obtained results about the microstructure evolution mechanism, deformation behavior and new FEM engines can provide the practices basis for the optimization of process design to attain quality products.