Study On The Microstructure And Deformation Mechanism Of High-Performance Low Oxygen Copper

In order to obtain high plasticity and high conductivity copper wire,this paper used micro-alloying method to prepare rare earth treated low oxygen copper.Then used SEM,TEM,EBSD,mechanical property testing,electrical conductivity testing and other means to study the effects of drawing deformation,annealing temperature and rare earth La addition on the microstructure,mechanical properties and electrical conductivity of low-oxygen copper.The microstructure and properties of low-oxygen copper under different drawing strains were studied.The results show that with the increase of the drawing strain,the strength of low-oxygen copper tends to rise first and then decrease slightly.The tensile strength reaches a maximum value of 435 MPa under ?=1.91 drawing strain;the changes on conductivity of low-oxygen copper is opposite to the strength,and the conductivity reaches the lowest value of 87.5%IACS under ?=1.91 drawing strain.With the increase of the drawing strain,the grains showed an obvious preferred orientation,and two wire textures of<001>and<111>were formed along the drawing direction;when the strain ?>1.91,TEM results show that recrystallized grains appeared in the structure.Results of the effect of annealing temperature on the structure and properties of cold-drawn copper wire show that:with the increase of annealing temperature,the tensile strength of copper wire decreases and the elongation increases;the degree of recrystallization of the grains in the copper wire structure increases,<111>wire texture disappears,and the strength of the<001>wire texture gradually weakens;after annealing at 200? for 30 minutes,the tensile strength of the copper wire is 237Mpa,and the elongation of the copper wire is 53.6%When compared with the original drawing state,the strength is significantly reduced,the elongation is greatly improved,and the volume fraction of the recrystallized region in the structure reaches 79.8%.The effect of rare earth lanthanum addition on the structure and properties of low-oxygen copper was studied.The results show that after the microalloying of rare earth La added,the oxygen content of the low-oxygen copper decreases and the electrical conductivity increases;with the increase of the amount of rare earth La,the structure of the low-oxygen copper gradually refines;The conductivity of the low-oxygen copper reaches a maximum of 102.4%IACS,and the unidirectional twisting value reaches a maximum value of 26 turns.After the rare-earth treated low-oxygen copper rod undergoes drawing deformation,the electrical conductivity is better than that of the ordinary low-oxygen copper.