| The influences of hot deformation conditions on the flow stress and microstructures of aluminium sheet used for easy-open-can prepared by synthetical technique of high-efficient melt-treatment of aluminium during hot deformation are studied by using dynamic thermal/mechanical simulation technology and OM and TEM analysis methods, aming at the currently existing problem of internall aluminium sheet used for easy-open-can. The material constants , the flow stress equation, the prediction model of microstructures and properties are derived from experimental data by linear regression analyses. The machanism of dynamic recovery and dynamic recrystallization of the material during hot deformation are discussed. The main results are as follows:(1)There are different dynamic softening phenomenons after peak stress at all experimental conditions. The influence of deformation temperature on the flow stress at elevated temperature is remarkable. The dynamic softening is more obvious, the flow stress and the value of true strain()corresponding to peak stress decrease, but the value of true strain() corresponding to the steady-state plastic flow increase with the increasing of deformation temperature. The influence of strain rate on the flow stress is more complicated. At lower strain rate(),the influence is remarkable, that is the flow stress and the value of increase, and the value of decrease with the increasing of strain rate. When the strain is higher than 1.0s-1, its influence is not obvious. The flow stress curve take on characteristic of multipeak at higher strain rate and deformation temperature. The interrelations of state flow stress ,strain rate and deformation temperature can be described by Arrhenius' equation, and the result indicates that the hot deformation of the material is controlled by thermally-activated process. (2)The material constants derived by the methods of graphing, linear regression and minimum deviation are to be equal, and the results derived by minimum deviation method are as follows: =189.952kJ/mol,=2.16×1013,=5.1914,=0.0218,the thermally-activated energy of the material is much higher than that of purity aluminiumor that of aluminium sheet used for pressure can, and lower than that of as-cast aluminium sheet used for easy-open-can, because the alloy elements such as Mn amd Mg ect., make the fault energy decrease and the cross-slip ability of dislocation decrease, which is favorable to dynamic recrystallization.(3)The semi-empirical equations of the flow stress at elevated temperature are derived from experimental data by polyelement linear regression analysis. Considening the influence of hot deformation conditions on the hardening rate and the dynamic softening rate, we also use Laasraoui and Jonas's flow stress model before peak stress and the Jonson-Mehl-Avrami model which is used to decribe the kinetics of recrystallization to establish the flow stress model at elevated temperature. The result fit into the pratically measured curves.(4)the influence of deformation temperature on microstructure during hot deformation is remarkable. The recrystallization grains size increases with the increasing of temperature. Whe deformation temperature is lower than 400℃, the distribution of grain structure is not uniform, and TEM analyses also show that the grains are elongated and dislocation density in the grains is high. When the temperature is higher than 400℃, the grains are equixed and distribute uniformly, and the dislocation density in the grains is low. The influence of strain rate on microstructures is complicated. The grains are coarser and the dislocation density in the grains is low when the strain rate is lower than 1.0s-1, the grains are elongated and the dislocation density increases obviously when the strain rate is higher than 1.0s-1.When the strain rate is equal to 10.0s-1, geometric dynamic crystallization might occurre by means of TEM analyses. The influence of strain on microstructure is also remarkable. The grains are elongated and there are few small...
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