Microstructure Control Of Pure Copper And Its Influence On Electrochemical And Mechanical Properties

Electrochemical mechanical polishing,as an important processing method to achieve both global and local planarization under low pressure conditions,has broad application prospects in precision machining.For materials of the same composition,grain size and grain distribution have significant impacts on electrochemical and mechanical properties.Therefore,it is of great scientific significance and engineering value to propose a microstructure control method and to study the influence of grain size on electrochemical and mechanical properties.In this paper,uniaxial compression of T2 pure copper at room temperature and heat treatment were carried out to establish recrystallization and grain growth model.The material constants were fitted with the consideration of initial grain size,deformation,heat treatment temperature and holding time.Based on the software DEFORM,the finite element model of cold rolling process for pure copper and heat treatment process was established.In order to determine the processing parameters for uniform micron-sized grains,the fitted recrystallization and grain growth model were used.The effects of friction and heat transfer during the rolling process were also taken into account.In order to expand the experimental range of the grain size effect on electrochemical and mechanical properties,the surface mechanical grinding treatment at room temperature was used to obtain a gradient nano-grain material with a certain depth of refinement.According to the results of electron backscatter diffraction measurement,the surface was refined to the nanometer scale.As the depth of the vertical direction increased,the grain size increased slowly,and submicron ultrafine grain structure still existed at a depth of 200 ?m.In order to study the effect of pure copper grain size on electrochemical performance,dynamic potential scanning was performed on samples with different grain sizes in 3.5 wt.% NaCl solution.The corrosion current density and surface shape after corrosion were studied.The relationship between grain size on mechanical properties was studied based on nanoindentation testing.The work could provide a reference for precision electrochemical mechanical polishing of industrial T2 pure copper.