Research On The Mechanism Of Microstructure And Texture Evolution Of Polycrystalline Copper During Cold Rolling

The finite element simulation of crystal plasticity is the combination of the constitutive relation of crystal plasticity mechanics and the finite element method to simulate the plastic deformation process of metals at grain size.The crystal plasticity theory introduces the plastic shear strain to describe the dislocation motion on the slip system.Using statistical ideas to treat discontinuous dislocation motion as a continuous plastic deformation process.Thus,linking microstructure to macroscopic continuum mechanics.Therefore,The crystal plastic finite element has outstanding advantages in the texture evolution and its influence on the performance of the simulated material deformation process.This article takes T2 copper as the research object,based on the uniaxial tensile test and one-way test for the cold rolling,combined with optical microscope(OM),electron backscatter diffraction(EBSD)and crystal plastic finite element simulation.Microstructure evolution of polycrystalline copper during cold rolling was studied,and the plastic deformation mechanism of polycrystalline copper cold rolling was revealed.The research results of this paper are as follows:(1)Based on the experimental characterization of polycrystalline copper in different tensile deformation of specimen and after rolling.It is found that dislocation slip is the main plastic deformation mechanism of polycrystalline copper.During the plastic deformation of polycrystalline copper,the grain morphology changed markedly and became slender along the direction of drawing or rolling.Plastic deformation would cause dislocations to proliferate,and the dislocation motion reconstruction intertwined to form dislocation walls,the Law Angle Boundaries inside grain interiors were increased;(2)EBSD experiments were carried out on polycrystalline copper specimens under different tensile and rolling deformation.During Uniaxial Tensile Deformation of polycrystalline copper,the intensity distribution of the pole figure was symmetrically distributed along the stretching direction as the increase of deformation amount,and formed a typical silk texture,which was called <111> silk texture.In the process of Cold rolling,With the increase of rolling deformation,the {111} surface texture was lip-shaped,and the intensity of {110} surface texture increased,which concentrated on the ND direction.It was indicated that the {110}<112> plate texture was stable;(3)Polycrystalline copper crystal plastic finite element model was set up in this paper.The stress-strain curve obtained by fitting the uniaxial tensile test by trial and error method determined the corresponding crystal plastic material parameters.The stress-strain behavior of polycrystalline copper under uniaxial tension,the texture evolution under different deformation and the non-uniformity of plastic deformation were simulated.The simulation results show that crystal plastic finite element method could well simulate the stress-strain mechanical behavior of polycrystalline copper.Moreover,the main features of texture evolution was captured.The <111> silk texture gradually was formed gradually with increasing of deformation degree,which indicated forming a preferred orientation;(4)Numerical simulation of polycrystalline copper cold rolling process was simulated by Crystal Plastic Finite Element Simulation.It was concluded that the polymorphic copper grains were not uniformly distributed during the plastic deformation process,and the deformation resistance of grain plastic deformation increased with raising of deformation strength.Due to the requirement of coordinated deformation of surrounding grains,the characteristics of multi-line slip were presented.As the increase of deformation,the number of activation of the slip system increased,and the contribution values of diverse slip system to plastic deformation were different.