Study On The Mechanism Of The Influence Of The Addition Of Trace Elements And The Alternative Rolling On The Thermal Stability Of Copper Grain Size

As an important conductive and thermally conductive material,the thermal stability of copper at high temperatures has always been a research hotspot in the fields of new energy and electronic communications.Aiming at copper at high temperatures,copper crystal grains are prone to rapid growth,resulting in stress relaxation,causing component failure,and endangering its service safety.In this study,Cu-0.12Mg,Cu-0.09Ca,Cu-0.1Y,Cu-0.06Zr,Cu-0.08Cr and other copper alloys with different trace element contents were prepared,and the microstructure evolution of the alloy during the forming process was analyzed.The law focuses on revealing the inhibition mechanism of Mg,Ca,Y,Zr and other elements on the grain growth behavior of the alloy after thermal exposure treatment at 650?/10 min and950?/10 min.In addition,The commutation rolling was used to study the evolution of the microstructure of copper during the forming process and the grain growth behavior after thermal exposure treatment at 650?/10 min and 950?/10 min,and combined with the observation of the metallographic structure(OM),Electron Backscatter Diffraction(EBSD),Scanning Electron Microscope(SEM)and Transmission Electron Microscope(TEM)have analyzed copper alloys with different trace element contents and commutated rolled copper in the process of forming and high temperature thermal exposure.The influence mechanism of stability.the result shows:(1)During the unidirectional rolling and alternative rolling process,the Brass and S textures of copper gradually increase with the increase of the amount of deformation,while the Cube textures gradually decrease.Compared with unidirectional rolling,under the same deformation conditions,the volume fraction of the S texture of copper is lower,and the Cube grain distribution is more uniform.(2)Alternative rolling can significantly improve the thermal stability of the grain size of copper at high temperatures.Compared with unidirectional rolling,the crystal grains of copper after commutation rolling are significantly refined after thermal exposure at 650?/10 min and 950?/10 min.With the increase of rolling deformation and the increase of thermal exposure temperature,the grain refinement effect of commutation rolling is more significant.The reason is related to the reduction of S texture and the uniform distribution of Cube grains.(3)The average grain size of pure copper after heat exposure at 650?/10 min and950?/10 min are 58.2?m and 198.0?m,respectively.The grain refinement effect of adding0.12 wt.%Mg element is the best,which obviously suppresses the grain size of copper after heat exposure treatment at 650?/10 min and 950?/10 min,which are 23.5?m and 82.5?m respectively.In addition,after thermal exposure at 950?/10 min,the?(Cu₂Mg)in Cu-0.12Mg alloy has a significant pinning effect on the grain boundary,which can reduce the grain boundary migration rate of the alloy grains,thereby hindering the grain growth It improves the thermal stability of the grain size of Cu-0.12Mg alloy at high temperature.(4)Trace Ca element is distributed in the copper matrix in the form of particles,which has a certain effect of grain refinement.The rare-earth element Y plays a role in removing impurities in copper.It forms high-melting-point oxides or rare-earth compounds by pinning at the grain boundaries,hindering the migration of the grain boundaries and inhibiting the growth of grains.Zr element and some impurity elements in copper form the corresponding compound as the crystallization core,which can increase the recrystallization temperature of the alloy.In addition,trace Zr element exists in the form of solid solution in the copper matrix,which plays a role in refining crystal grains.(5)Compared with copper,under 95%deformation,after 650?/10 min and 950?/10min thermal exposure treatment,add 0.12 wt.%Mg,0.09 wt.%Ca,0.1 wt.%Y and The 0.06wt.%Zr element significantly weakens the Cube texture in the alloy,and increases the volume fraction of Brass texture and Copper texture,so that the copper alloy exhibits better thermal stability of grain size at high temperatures.