Investigation On The Mechanisms Of Electric Drawing Of High Purity Nickel And Copper Wires

Under the electric field,the plasticity of metallic materials increases and the deformation resistance decreases,which benefits to the material processing and is thus drawn increasing research interest.The electric effect and Joule heat effect were involved in the processing,of which the underlying mechanisms on the deformation mechanism is unfortunately not yet clear,it has great research significance.Consequently,the present study chose high purity nickel and copper wires of face centered cubic structure as model materials to subject to tensile and drawing under plus electric field.Due to the limitation of fine silk material,it is not easy to directly characterize dislocations,so the focus is on the changes in microstructure morphology and texture,and the following conclusions were obtained:(1)Under electric field,tensile stress decreases and the elongation increases when the peak current density of nickel and copper wires is 25.5 A/mm2 and 19.1 A/mm2,respectively.On the contrary,as the peak current density of nickel and copper wires is 25.5 A/mm2 and19.1 A/mm2,respectively,both the tensile stress and the elongation decrease.(2)During electric tensile,the transformation from < 001 > to < 111 > fiber texture is enhanced for both nickel and copper wires,and the activation and the gliding of dislocations were promoted.(3)During electric drawing,the temperature rising for both nickel and copper wires is related to the drawing strain and the peak current density.Temperature rising increases with peak current density at given drawing strain.(4)The drawing microstructure was influenced by applying electric field.The electric effect mainly influences the texture development,namely,the transformation from < 001 >fiber to < 111 > one was enhanced.Joule heat leads to the occurrence of recrystallization and extra textural component except for < 111 > fiber.(5)Electric effect mainly influences the dislocation activity.Both the starting and the gliding for dislocations were promoted during drawing under electric effect,resembling the influence on electric effect on the tensile behaviors.