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- Type of Document: M.Sc. Thesis
- Language: Farsi
- Document No: 48944 (07)
- University: Sharif University of Technology
- Department: Materials Science and Engineering
- Advisor(s): Serajzadeh, Siamak
- Abstract:
- In this work, annealing procedure of cold-deformed AA5052-SiC composite has been simulated by using cellular automata approach and the effect of SiC second phase on softening kinetics has been studied. To do so, site saturated nucleation has been employed to establish initial microstructure. In addition, topological changing due to deformation has been implemented on the microstructure. During annealing, recovery and recrystallization phenomena occur simultaneously, and it has strong effect on the annealed microstructure. Therefore, during annealing, recrystallization and recovery has been considered simultaneously and decreasing in the stored energy, which has developed during deformation due to isothermal recovery has been calculated by the model. Furthermore, Recrystallization has been considered in the terms of nucleation rate, grain boundary movement and grain boundary curvature. In order to obtain phenomenological model of recovery of this alloy as well as to verify the model predictions, experimental studies are performed. Cold deformation has been carried out by means of uni-axial compression on the cylindrical samples. Heat treatments have been conducted at temperatures 220°C, 240°C, 260°C and 300°C and different durations. Then, the shear punch test and double-hit compression tests have been employed to determine the recovery kinetics of heat treated composite. Also, samples have been annealed isothermally for different durations in salt bath at 340 °C and 380 °C where the flow stress changing and hardness kinetics have been measured for static recrystallization behavior. Modelling results show logarithmic decay of flow stress with increasing in time and temperature as well as, recrystallization kinetics acceleration and grain refining due to presence of second phase particles. Activation energy of static recovery and static recrystallization have been calculated 170.35 kJ/mol and 195 kJ/mol respectively, which is lower than AA5052. The comparison between experimental and optical microscopic results with model prediction illustrates a reasonable agreement. Thus, the model can be used for prediction of microstructure and recrystallization kinetics
- Keywords:
- Static Recovery ; Cellular Automata ; Second Phase Particles ; Softening Kinetics ; Static Recrystallization ; Aluminum Alloy 5052 ; Microstructure Simulation
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