Investigation On Microstructure And Mechanical Property Of Al-Cu Alloy During Process Of Deformation And Recrystallization

In this work,0.3%copper was added to ultra-high purity aluminum, after coldrolled at different reduction, the material was annealed at different temperature andholding time. The experimental techniques including micro-hardness testing, tensiletesting, electron channel contrast and electron backscatter diffraction were employed tostudy the work hardening microstructure evolution, micro-texture evolution andmisorientation distribution. Tensile testing was carried out to investigate the effect of thecopper on the mechanical properties of Al-0.3%Cu alloy. The main results are asfollows:â‘ When the reduction is low, as the reduction increase, the hardness of Al-0.3%Cualloy increase like straight line. And when then reduction is medium and high, thehardness of Al-0.3%Cu alloy increase like parabolic curve with the reductionincreasing.â‘¡As the reduction increase, the original cube texture component and the lowangle grain boundaries decreases. When the reduction is more than80%, the high angelgrain boundaries of the misorientation ranged from45°to60°increase quickly. This isrelated to the dynamic recovery and dynamic recrystallization occur in the high-strainrolling Al-0.3%Cu alloy.â‘¢The recrystallization temperature of98%cold rolled Al-0.3%Cu alloy is in therange of175℃²00℃, and the activation energy for recrystallization is96.02KJ/mol.The materials with grain size from0.23μm to28μm are also obtained by accurate heattreatment. As the annealing temperature increase, the rolling texture componentdecrease, but the cube texture increase slowly, and the low angle grain boundaries aretransformed into high angle grain boundaries.â‘£A good strength is obtained from ultra-fine grain Al-0.3%Cu alloy, during thisprocess the yield point phenomenon is avoided. The plastic instability phenomenonexists in other ultra-fine grain aluminum materials is effectively avoided. Theappearance of negative deviation of Hall-Petch relationship is delayed.⑤The strain rate sensitivity parameter of ultra-fine grain Al-0.3%Cu alloy is0.07.A passivation of strain rate sensitivity is obtained when the strain rate is more than1×10^-3/s.