Sharif Digital Repository

Accumulative spin bonding as a severe plastic deformation process results in a finer microstructure through multi-pass processing. This method consists of successive and repeated preparation of internal and external surfaces of two similar tubes, simultaneous flow forming of two tubes and production of a tube with the same thickness as the primary one. This word was conducted to study the effect of different rotational speeds and different cooling environments on the mechanical properties and microstructure of AA1050 tubes. The samples were prepared with 0.8 mm thickness and 92.8 mm internal diameter through four passes of ASB with 250, 500, 710 rpm under air, water and acetone cooling... 

Hot deformation behavior of Al-SiC nanocomposites was investigated in this study. Aluminum powders with mean size of 60 micron and SiC nanopowders (mean size of 45nm) in amounts of 1 and 2 volume percents, as reinforced part, were mixed and milled for 40 hours by planetary ball mill. After degassing at 450 oC for 1 hour, milled powders were pressed into Aluminum cans (in Argon atmosphere) and then hot extruded. Extrusion ratio was 1:14. High density billets (with 98% of theoretical density) were produced because of that high extrusion ratio. TEM microstructure studies showed that fine distribution of reinforcements and Aluminum Oxides obtained via this procedure. Hardness and Uniaxial... 

Metallic multilayer composites provide remarkable mechanical, electrical and magnetic properties. These kinds of composites have been recently processed by severe plastic deformation (SPD) methods. Accumulative roll bonding (ARB) is one of the SPD processes in which accumulation of strain by repeating cycles, leads to the ultra fine grained materials. The goal of this research is manufacturing of Al/Ni composite sheets by ARB process considering the effects of thickness and number of initial sheets on their mechanical properties and microstructures. The initial composites were produced by commercially pure Al and Ni as the matrix and the reinforcement, respectively. Thickness of the Al... 

At this study, nano structure sheet composite produced by1100 and 3004 strips using Accumulative role banding then mechanical and physical properties of the composites were investigated. After surface preparation, primary composite samples produced by putting different layers on each other and then rolling. The rolling was occurred in two steps; thickness reduction at first and second step were about 50% and 34%, respectively. ARB process were done till ninth cycle for Primary composite samples. To investigate mechanical properties of the samples, hardness, micro hardness and tensile strength tests have been done. Furthermore, micro structure of selective samples were studied by light... 

Magnesium and its alloys have gained significant attention in medical applications due to their good biocompatibility. However, their widespread use has been limited by some inherent drawbacks, such as poor mechanical properties. The ZX00 magnesium alloy has been used in medical applications, including implants, due to its slow degradation rate and good ossification. However, this alloy lacks sufficient strength and ductility. The severe plastic deformation method can create an ultrafine grain structure and improve mechanical properties. In this study, to improve the mechanical properties and create an ultrafine grain structure, the multi-directional forging process was performed on... 

Nowadays, the application of magnesium alloys as biodegradable implants in the medical industry has garnered significant attention. However, the low mechanical properties and rapid degradation rate of pure magnesium implants in the biological environment have hindered their widespread use for clinical applications. Magnesium-calcium alloys, due to their low degradation rate and promotion of faster bone healing, have become attractive choices for orthopedic applications. Nevertheless, the micro alloy X0 used in this study lacks sufficient strength and flexibility, limiting its potential applications. Utilizing severe plastic deformation methods to create ultrafine microstructures can greatly...