In the diploma work we dealt with hot workability of the aluminium alloy EN AW 3003. Cylindrical pressure tests were performed on the Gleeble 1500D thermo-mechanical state simulator. We performed tests at the temperatures 300 °C, 400 °C and 500 °C at the deformation rates of 0.1 s-1, 1 s-1, 10 s-1. We edited the data from pressure tests in program Origin, where we produced flow curves, from which we found, that the maximums stresses occur later at lower temperatures and earlier at higher temperatures. The apparent activation energy for the hot deformation of the investigated aluminium alloy was calculated from the maximum stresses and it yields 195,07 kJ ∙ mol-1. Using the parameters of the Sellars equation, we have calculated the maximum stresses. The values obtained, closely match the measured values.
The flow curves were derivated to obtain a diagram of hardening speed as a function of true stress. Based on the analysis of the hardening speed diagrams with the "Poliak-Jonas" criterion, we could determine the critical stresses for the beginning of dynamic recrystallization. We found that the process of dynamic recrystallization begins faster at higher temperatures and low deformation rates than at lower temperatures and high deformation rates.
After the experiments, the samples were cut in half and prepared for metallographic analysis. This was done using an optical microscope at 25x and 100x magnification. After analysis of microstructures, we found that in some samples static recrystallization occurs instead of dynamic recrystallization.
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