Tailoring And Evolving Of Annealing Texture Of Deformed Copper Foil

As a graphene deposition substrate,the surface grain crystallography orientation of rolled copper foil is one of the important factors that affects the growth behavior of graphene.Oxygen-free high-conductivity pure copper and rolled copper foil with a purity of 99.94% were used in this investigation.The bulk pure copper was cold–rolled to a reduction of 40% and 70%.Half of all sample were indented and the rest remain unprocessed.Then all samples were annealed for one hour,there were 12 sets of annealing temperatures range from 100 ℃ to 1040 ℃.The copper foil samples were either flat or curved during the annealing process.Electron back scatter diffraction and X-ray diffraction analysis techniques were used to systematically investigate the effect of deformation and micro-indentation on the evolution of microstructure and texture of bulk copper after isothermal annealing at different temperature for one hour,and to systematically study the effect of the placement mode and micro-indentation on the evolution of microstructure and texture of copper foil after isothermal annealing at different temperature for one hour.List below are major results achieved in this thesis:For cold-rolled 40% reduction bulk sample,the whole annealing process can be divided into three stages according to the characteristics of microstructure of the samples after annealing.Stage one: Annealing at 100 ℃ ～ 200 ℃ for one hour,the microstructure and texture basically maintain what deformed sample like;Stage two:Annealing at 250 ℃ ～ 700 ℃ for one hour,the samples have been completely recrystallized and recrystallized gains grow larger.But the texture is weak;Stage three:Annealing at 800 ℃ ～ 1040 ℃ for one hour,the recrystallized grains continue to grow much larger and obtain a strong brass texture.For cold-rolled 70% reduction bulk sample,the whole annealing process can also be divided into three stages for the same reason.Stage one: Annealing at 100 ℃ ～200 ℃ for one hour,the microstructure and texture basically maintain what deformed sample like;Stage two: Annealing at 250°C ～ 300 ℃ for one hour,the samples have been just completely recrystallized and the texture is weak;Stage three: Annealing at500 ℃ ～ 1040 ℃ for one hour,the recrystallized grains continue to grow much larger and obtain a strong brass texture.For the flat placed copper foil,the whole annealing process can be divided into four stages.Stage one: Annealing at 100 ℃ for one hour,the microstructure remains unchanged;Stage two: Annealing at 150 ℃ and 175 ℃ for one hour,the material starts to nucleate and most of the nuclei have cube orientation;Stage three: Annealing at200 ℃ ～ 900 ℃ for one hour,the recrystallization grains keep growing and obtain strong cubic texture;Stage four: Annealing at 1000 ℃ and 1040 ℃ for one hour,the recrystallized grains grow to a centimeter scale and the cube orientation decrease.For the copper foil which was bend placed in a 35 mm quartz tube,the entire annealing process can be also divided into four stages that consistent with flat placed samples.But the temperatures range in stage three and stage four should change into200 ℃-1000 ℃ and 1040 ℃ respectively.For the copper foil which was bend placed in a 80 mm quartz tube,the experimental results are similar to flat placed samples when annealed at 700 ℃ ～1000 ℃ for one hour.While annealing at 1040 ℃ for one hour,samples with indentation possessed(111)and(116)planar texture were observed.The process conditions above could achieve a proper substrate orientation which is suitable for single crystal grapheme growth.Moreover,micro-indentation could be possible preferential nucleation sites but have very limited effect on the overall microstructure and texture of the material.