Study On The Technological Parametters Of Low Pressure Core Filling And Rolling For Preparation Of Copper Cladding Aluminum Conductive Rows

Beacause of its low cost,high efficiency and other characteristics,copper and aluminum composite conductor has been widely used.But the current production processes are inadequate.In this paper,copper-aluminum composite bars were prepared by low-pressure core filling process,and then conductive rows were prepared by rolling.The influence of the deposition time of K2ZrF6 saturated solution,the preheating temperature of copper pipe,solidification temperature,and pressure of core-filling and the rolling temperature,amount of pressure,speed,pass on the copper and aluminum interface reaction,the transition layer thickness,phase composition,bonding strength and electrical conductivity were investigated.By experimental and finite element simulation method,the rolling process temperature field and rolling force changes were studied.The results show that the anti-oxidation film prepared by cooling the deposition of K2ZrF6 supersaturated solution at about 90? for 5min can effectively prevent the copper tube from being oxidized during the preheating process.When using 0.2MPa-0.5MPa secondary supercharging,copper clad aluminum rods have fewer defects.The effect of the temperature of aluminum liquid on the thickness of copper-aluminum interface is not obvious.The preheating temperature of copper rod has a significant effect on the diffusion of aluminum to copper side,the intermetallic compound content and the thickness of the transition layer are increases with the rising preheating temperature.By XRD and chemical composition analysis,we found that the intermetallic compounds in the diffusion layer are mainly CuAl2 and CU3Al4.Among them,CuAl2 is preferentially formed on the copper side.When the intermetallic compound content increases,the interfacial bonding strength decreases.However,when there are defects in the interface,the effect of the defect on the interface bonding strength will be dominant.Although the rolling process further spreads the atoms,it has a positive effect on the reduction of internal defects in copper-clad aluminum rods.Comparison of the same low-pressure core parameters of copper-clad aluminum rod before and after rolling,we found that the interface bonding strength and electrical conductivity of' copper clad aluminum conductive row are higher than copper clad aluminum rods.Rolling results showed that when the rolling temperature was 400 ?,the interface bonding strength and conductivity were best.Over 40%of the rolling reduction will cause the cracking of the sample.With the increase of the rolling reduction from 10%to 30%,the defects such as porosity and shrinkage of the sample decrease,and the mechanical and metallurgical bonding of the interface were produced.The interfacial electrical resistivity decreases and the bonding strength increases.With the rolling pass increased from 1 to 3,the interface bonding strength increased,the electrical resistivity decreased;rolling pass was more than 3,the interface began to crack.With the increase of rolling speed from 0.3m/s to 0.7m/s,the interfacial bonding strength increases and the electrical resistivity decreases.When the rolling speed is greater than 0.7m/s,the interfacial defects increase sharply,the bonding strength decreases,and the electrical resistivity increases.The finite element simulation of rolling shows that the temperature of the copper tube decreases faster than that of the aluminum core,and the temperature tends to be the same when 200s later.The maximum rolling force increases with increasing rolling reduction and rolling pass,meanwhile the magnitude is increasing.