Simulation And Ecperimental Study On Equal Channel Angular Pressing For Pure Copper

With the widely application of nanometer materials and ultrafine-grained material,People began to pay attention to the effect of large plastic deformation on the grain refinement of the material,the ECAP extrusion technology has been widely recognized by researchers because of it has fine grain refinement effect.In the process of deformation,the field quantities such as temperature,stress,strain closely related to the grain refinement effect,while the field quantities are decided by ECAP mold structure and technological parameters,So in order to obtain good grain refining effect,it is necessary to comprehensively study the influence of different parameters on the ECAP extrusion effect.In this paper,the DEFORM-3D software is used to carry out the numerical simulation and experimental study of ECAP systematically.The effects of different process parameters on the extrusion are analyzed.The results are as follows:1.Based on the ECAP finite element model of pure copper,this paper discusses the load,temperature,equivalent stress,strain level and distribution of samples in the process of ECAP extrusion deformation.Study the effects of process parameters(inside and outside angle of the mould,friction coefficient,extrusion temperature,extrusion speed,extrusion path and pass)on the ECAP deformation,get optimum technology parameters(angle for 90°,the mold external radian angle is 20°,the friction coefficient is 0.1,the extrusion speed is lmm/s,the extrusion temperature is 20 ?,extrusion path for Bc),so as to guide the ECAP experimental study.2.Back pressure in conventional ECAP mold,found back pressure from 10MPa to 320MPa,with the increase of the maximum load back pressure increases,and the.equivalent strain distribution uniformity is also gradually more uniform,especially in the back pressure in the 160MPa strain distribution was better.3.Numerical simulation of the UV-ECAP find its load decreases,the average equivalent strain increases,and the uniformity distribution of equivalent strain were improved which compared with conventional ECAP.Analyzed the influence of the amplitude of extrusion process,the results showed that with the increase of amplitude,extrusion load will decrease continuously,the average equivalent strain increases,and the uniformity distribution of equivalent strain was improved,When the amplitude reaches 20 ?m,the specimen obtained the best load and equivalent strain.4.The ECAP mould which used in this paper were self-designed and specialized custom-made,ECAP extrusion experiments were carried on presser,after 1 pass the change trend of extrusion pressure and simulated load-displacement basically the same,specimen deformation geometry is roughly same.According to the size and distribution of grain size after single pass and multi pass extrusion,the size and distribution of the samples were found.So the experimental results verify the reliability of the numerical simulation.