Controlling and modelling of twin induced strain localization in rolling of magnesium AZ31

İsmail, Kübra
Formability of AZ31 Magnesium alloy has certain limits below 200 ℃ and depends strongly on temperature, due to the strain localization and shear banding associated with the twinning activity. In this thesis, magnesium sheets with basal, off-basal (90° tilted) and mixed (50% basal + 50% off-basal) textures are rolled between room temperature and 165 ℃ to understand and control the twinning-induced localizations. By increasing strain from 0.1 to 0.6 and raising the temperature, the fraction of flow localized regions increases and the strain intensity in these regions is controlled by the starting texture. The sheet with basal texture develops the most intense localizations at room temperature and fails by shear banding at only 0.16 strain. Off-basal sheet, on the other hand, has similar fraction of twins and localizations but capable of deforming twice the strain (0.36) without shear banding. Maximum uniform strains increase with temperature and reach to 0.60, 0.50, and 0.33 at 165 ℃ for off-basal, mixed, and basal textures, respectively. When the fraction of strain localized regions and the strain intensity in them are incorporated into a model, it was possible to predict the maximum rolling strain for a given starting texture and temperature.


Multiscale & in-situ forming analysis of AZ31 magnesium alloy under different strain paths
Alkan, Kıvanç; Efe, Mert; Department of Metallurgical and Materials Engineering (2018)
Formability of AZ31 Magnesium alloy is limited and strain path dependent below 180 ᵒC. In this thesis, formability behavior and fracture mechanisms of AZ31 Magnesium alloy are investigated by in-plane biaxial testing. In-situ and multiscale strain analysis reveal the microstructural features and deformation mechanisms responsible form the unusual forming behavior of the AZ31 alloy and offer possible solutions to control the forming defects and instabilities. The strain measurements show that the equivalent ...
Electrolytic magnesium production using coaxial electrodes
Demirci, Gökhan; Karakaya, İshak; Department of Metallurgical and Materials Engineering (2006)
Main reason for the current losses in electrolytic magnesium production is the reaction between electrode products. Present study was devoted to effective separation of chlorine gas from the electrolysis environment by a new cell design and thus reducing the extent of back reaction between magnesium and chlorine to decrease energy consumption values. The new cell design was tested by changing temperature, cathode surface, current density, anode cathode distance and electrolyte composition. Both the voltages...
Akturk, Fatih; Sezer Uzol, Nilay; Aradag, Selin; Kakac, Sadik (2015-01-01)
In this study, the thermal and hydrodynamic performance analyses of sa elected gasketed-plate heat exchanger with different number of plates are performed experimentally. A gasketed-plate heat exchanger (GPHE) test set-up is designed and constructed to perform experimental measurements for thermal and hydrodynamic performance analyses of plate heat exchangers. The experiments are performed for an industrial chevron-type plate heat exchanger under different flow conditions for a wide range of Reynolds number...
Yurtseven, Hasan Hamit (World Scientific Pub Co Pte Lt, 2013-09-20)
We calculate the Raman frequencies of the E-g mode and, the low and high frequency T-g mode as a function of temperature at a constant pressure of 2.85 kbar in the alpha-phase of solid nitrogen. The Raman frequencies of those lattice modes are calculated using the volume data from the literature at various temperatures (2.85 kbar) for the alpha-phase of solid N-2 through the mode Gruneisen parameter. Our predicted Raman frequencies can be compared with the experimental data and by this method the Raman freq...
Analysis and calculation of the magnetization, magnetic susceptibility and the specific heat close to phase transitions in heterometallics
Dugan, E. Kilit; Yurtseven, Hasan Hamit (Elsevier BV, 2019-10-01)
The temperature dependence of the magnetization for DMFeNi and DMFeCu is calculated by the molecular field theory and it is also analyzed as functions of temperature and the magnetic field by the power-law formulae close to the phase transitions in these compounds by using the observed data from the literature. From the analysis, values of the critical exponents beta (temperature-induced order parameter at H = 100 Oe) and delta (field-induced order parameter at T = 2 K) are deduced. Also, using the observed...
Citation Formats
K. İsmail, “Controlling and modelling of twin induced strain localization in rolling of magnesium AZ31,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Metallurgical and Materials Engineering., Middle East Technical University, 2019.