Size Effect On Pure Copper Micro Flexible Rolling And Numerical Simulation Study

With the increasing proportion of high precision electronic equipment and artificial intelligence products in the market,the demand for micro parts is increasing day by day.However,the miniaturization of dimensions brings about various special size effects in the field of micro-forming.It is necessary to study the size effect in micro flexible rolling due to the fact that the micro rolling technology can not achieve the desired effect in actual production and limit the development of micro flexible rolling technology.In this paper,pure copper samples with thickness of 0.1mm,0.2mm and 0.3mm respectively were annealed to study the effect of size on the mechanical properties of pure copper.The effect of size effect on the deformation capacity of pure copper was studied by means of numerical simulation,micro-And dislocation density.The main findings are as follows:(1)When the annealing temperature is 500?,the grain growth rate is almost equal.With the increase of annealing temperature,the grain size difference between samples increases,and the grain growth rate of pure copper sheet with thickness of 0.3mm is the biggest.(2)As the grain size increases or the thickness decreases,the elongation and tensile strength of pure copper decrease gradually.The grain size and thickness have an important influence on the fracture mechanism of pure copper.With the increase of grain size or the decrease of thickness,the fracture mechanism of the specimen changed from mixed fracture to slip fracture.(3)With the increase of the grain size or the decrease of the thickness,the non-uniform deformation of the rolling edge increases,the edge bulge is becoming more and more obvious,the spread of uneven increase and the plasticity of the material becomes unstable.The rolling force decreases gradually,the SDF increases obviously,which indicates that the rolling force instability increases.(4)With the increase of grain size,grains are elongated along the rolling direction,when the grain size increases to 211?m,the grain shape becomes continuous lamellar structure.From the rolling thick zone to the rolling thin zone,the reduction rate gradually increases,the grain orientation gradually forms the preferential orientation and is flattened and elongated,showing a lamellar structure along the rolling direction.(5)With the increase of grain size,the dislocation density at the grain boundaries gradually decreases and the dislocation segregation phenomenon is not obvious.As the amount of deformation increases,subgrain appears in the grains of pure copper,and the original single crystal grain is divided into several subgrains.With the increase of specimen thickness,the dislocation density becomes larger,dislocation entanglement becomes more and more serious,and the required deformation force is larger when plastic deformation occurs.(6)As the grain size increases,the elongation and tensile strength of the material decrease gradually.The elongation of the specimen decreases with the decrease of the thickness.The specimen with the thickness of 0.059 mm has the highest tensile strength,While the thickness of 0.131 mm sample the lowest tensile strength.The fracture modes of all samples after rolling are ductile fracture.The number of dimples in the middle fracture surface decreases with the increase of grain size or the decrease of the thickness of the rolled piece,and the toughness deteriorates.