Study On The Performances And Fabrication Methods Of Cu-4.0Ag Alloy Fine Wires With High Strength And Corrosion-Resistance

Firstly,the?8.0mm Cu-4.0Ag alloy rod was prepared by hot continuous casting method.And then the?0.05mm Cu-4.0Ag alloy fine wires with high strength and high conductivity were obtained by continuous cold drawing.The microstructures and properties of the Cu-4.0Ag alloy wires were studied during the plastic deformation.The graphene-coated Cu-Ag alloy wires were prepared by coating graphene on the?0.1mm Cu-4.0Ag alloy wires and the corrosion resistant behaviors of the wires were investigated.The grains of the?8 mm Cu-4.0Ag casting oriented along longitudinal direction with silver particles are uniformly precipitated.It owns high electrical conductivity and excellent plastic deformation and the electrical conductivity,tensile strength and elongation after breakage are 86.44%IACS and 201.50 MPa and the 40.75%,respectively.?0.05 mm Cu-4.0Ag alloy fine wires are high strength and high conductivity which are 1.02 GPa and 77.20%IACS,respectively.The Hollomon relationship was used to study the work-hardening phenomenon during the drawing process.The results showed that the hardening index increased from 0.20 to 0.42,resulting in a 49.41%increase in Vickers hardness.The resistivity variation during the deformation process by the Boltzmann function showed that the resistivity increased to0.02245?·mm²/m and tends to be stable.The microstructures of specimens with different deformations during plastic deformation were investigated by EBSD.The inverse pole figures of the as-cast rod showed that the existence of silver particles makes the overall grains deviate slightly from<100>and the orientation between adjacent regions is less than 5°,and Schmid factor showed that eight slip systems can be activated.The misorientation angle and the difference between adjacent alignment bands of texture increased during the plastic deformation processing.When the deformation amount reaches 2.40 meanwhile,the plastic deformation resistance obviously increases for that the misorientation angle is between 40°and 60°and there are only four activated slip systems.The corrosion resistant behaviors of Cu-4.0Ag alloy wire coated by graphene layer were tested by the three-electrode electrochemical detection method.The polarization curve?PC?and electrochemical impedance spectroscopy?EIS?were tested respectively.The SEM showed that after the corrosion reaction occurs,the protective effect of the GCu-4.0Ag coating was in good condition,and the substrate of the wire is not exposed.The PC showed that the corrosion potential of GCu-4.0Ag wire is positively shifted and the corrosion current density is reduced by 2⁴ orders of magnitude.The polarization resistance?R_p?is obviously higher than 2³ order magnitude through the linear fitting of Tafel by strong polarization method,which indicates that the corrosion reaction is more difficult to produce.The Nyquist diagram of EIS showed that the conductor capacitance arc of GCu-4.0Ag wires is greater than the original conductor.The corresponding Bode plot shows that the peak value of phase angle of GCu-4.0Ag wires is higher than that of Cu-4.0Ag ones.A wider frequency range is existed.Meanwhile,magnitude of impedance modulus in the low-frequency region is about 3 orders higher than that of original wires,which shows that the corrosion resistance increased sharply.The R?Q?R?CR???equivalent circuit fitting results showed that the corrosion resistance of GCu-4.0Ag wire increased by 2⁴ orders of magnitude than that of original one.The capacitance value(C_dl)decreased by 2³ orders of magnitude,which further indicated that the coating graphene was effective in preventing corrosion from isolating ions in the electrolyte.