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constrained-groove-pressing--cgp
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Effect of Inter-pass Annealing During Severe Plastic Deformation on Microstructure and Mechanical Properties of Low Carbon Steel
, M.Sc. Thesis Sharif University of Technology ; Kazeminezhad, Mohsen (Supervisor)
Abstract
Low carbon steel is widely used in the automotive industry by improving ductility and minimizing hardness to achieve greater strain. Applying severe plastic deformation to metals and alloys increases strength and decreases ductility. In the process of severe plastic deformation, the pressure is limited in the grooved form. Low carbon steel, after two passes of severe plastic deformation, experiences a rapid drop in strength in addition to ductility, which may indicate the presence of microcracks. Therefore, in this research, annealing between passes during the pressure process in the form of limited grooves has been used so that without a serious decrease in strength, some ductility...
Investigation of Microstructure and Mechanical Properties after Performing Cold Rolling and Annealing on Severely Deformed Low Carbon Steel
, M.Sc. Thesis Sharif University of Technology ; Kazeminezhad, Mohsen (Supervisor)
Abstract
According to the conducted research, severe deformation of low-carbon steel sheets using the constrained groove pressing method causes a decrease in grain size and increases the strength and hardness of the sample after one pass. However, continuing this process in subsequent passes does not significantly increase strength and hardness, and sometimes it remains constant. Therefore, in this project, cold rolling has been used to improve the strength of the steel sheet and improve the surface smoothness of the final piece. After severe deformation and rolling due to the high applied strain, the strength of the sample increased and the percentage of its elongation decreased. Therefore,...
On the evolution of flow stress during constrained groove pressing of pure copper sheet
, Article Computational Materials Science ; Volume 45, Issue 4 , 2009 , Pages 855-859 ; 09270256 (ISSN) ; Kazeminezhad, M ; Mani, A ; Rafizadeh, E ; Sharif University of Technology
2009
Abstract
Using a mechanical model and dislocation density based model, the evolutions of dislocation density and flow stress of pure copper during constrained groove pressing (CGP) process are investigated. In this regard, the strain and strain rate are achieved from the mechanical model and then input into the dislocation model. To verify the predicted flow stress, the process of constrained groove pressing is performed on the sheets of pure copper from one to three passes. The predicted flow stresses are compared with the experimental data and a good agreement is observed. Also, it is found that during the straining of the copper sheet in CGP process, the dislocation density and strength dropping...
Friction Stir Welding of Severely Deformed Aluminum Using Hybrid Powders
, M.Sc. Thesis Sharif University of Technology ; Movahedi, Mojtaba (Supervisor) ; Kazeminezhad, Mohsen (Supervisor)
Abstract
Severe plastic deformation (SPD) is an ideal approach to fabricate light-weight alloys, such as aluminum alloys, with ultrafine-grained (UFG) structure up to nano-scale. Thus, it is known as a process that boosts the strength of materials. This method is also adopted to enhance the specific strength of materials, which is essential in the transportation and aerospace industries. Because of limitations like load capacity, and as a result, low-size productions, it is not possible to use them in industries. A practical solution is to join the productions and fabricate them on bigger scales. Welding of SPDed materials by employing solid-state welding techniques is appropriate for joining UFG...
The Effect of Deformation in Grooved Die and Heat Treatment on Formability and Mechanical Properties of a Precipitation Hardenable Aluminum Alloy
, M.Sc. Thesis Sharif University of Technology ; Karimi Taheri, Ali (Supervisor) ; Serajzadeh, Siamak (Supervisor)
Abstract
The precipitation hardenable 7075 Aluminum Alloy is one of the most important heat-treated aluminum alloys. The high strength of this alloy has led to its widespread use in the manufacture of various components in the automotive, aerospace, marine, defense and military industries. Although the production costs of this alloy sheet are high, but since the 7075 aluminum alloy has the capacity to be as strong as steels, by reducing the production process and thus reducing production costs, this alloy can be used more widely in various industries. Therefore, in this study, the mechanical properties of the 7075 aluminum sheet are improved by a new quenching method in the die (HFDQ), which is a...
Predicting the ultimate grain size of aluminum sheets undergone constrained groove pressing
, Article International Journal of Advanced Manufacturing Technology ; Volume 86, Issue 5-8 , 2016 , Pages 1639-1658 ; 02683768 (ISSN) ; Firooz, S ; Jandaghi, M. R ; Khalaj, G ; Nazari, A ; Sharif University of Technology
Springer-Verlag London Ltd
2016
Abstract
The grain size of constrained groove pressed aluminum has been predicted through the genetic programming approach. “Sheet thickness,” “elongation,” “yield strength,” “ultimate tensile strength,” “total strain,” and “hardness,” along with “primary grain size” of the ultrafine-grained sheets were utilized as input parameters to obtain the ultimate grain size. A total number of 73 available data in the literature were gathered and randomly divided into 60 and 13 sets for algorithm training and testing, respectively. Among the presented models, the one with best performance utilized parameters of total strain, ultimate tensile strength, and primary grain size with 40 chromosomes, 10 head sizes,...