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RISS 인기검색어
- 검색키워드
- 저자 : Behrouz Bagheri (검색결과 5 건)
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Behrouz Bagheri,Mahmoud Abbasi,Farzaneh Sharif,Amin Abdollahzadeh 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.9
A developed version of friction stir brazing (FSB) entitled friction stir vibration brazing (FSVB) was presented to fabricatelow carbon steel joint using %67wt Sn-%33wt Pb alloy as a braze metal. This attempt aims to analyze the role of mechanicalvibration and rotational speed on microstructure and mechanical behaviors of the brazed samples. Furthermore, the thermalanalysis, the thickness of intermetallic compounds (IMCs) layers, and void volume percentage at the joint interface werestudied. It was concluded that the temperature during the joining process increased and the coherency of the joint interfaceenhanced while FSVB was applied instead of FSB. In addition, the grains in the joint zone under the FSVB process weresmaller than those produced under the conventional FSB process. The results also showed that the mechanical performance,namely hardness, and shear strength increased and the thickness of the IMCs layer along with the void volume percentagein the brazed sample decreased as rotational speed increased from 850 to 1150 rpm. The results indicated that rotationalspeeds over 1150 rpm had detrimental effects on mechanical properties. This is related to the effect of high heat input andinduced temperature on brazing flow and filler-base metal interaction.
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Advanced Approach to Modify Friction Stir Spot Welding Process
Behrouz Bagheri,Mahmoud Abbasi,Amin Abdollahzadeh,Hamid Omidvar 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.10
Nowadays, friction stir spot welding (FSSW) is used in automotive, rail vehicle construction, the aerospace industry, andelectrical industry. In the current research, a modified version of the FSSW process entitled friction stir spot vibration weldingwas introduced to join Al5083 specimens. The joining specimens were vibrated normal to the tool movement direction,while the joint position cooled by passing coolant through the fixture. Different characteristics of developed joint namelymicrostructure, mechanical properties, corrosion behavior were studied. The results showed that stir zone grain size decreasedsignificantly as the vibration was employed and the joint position was cooled. It was found that vibration enhanced thedynamic recrystallization and coolant decreased the grain growth. Both led to enhanced grain refinement in the stir zone. The results also indicated that shear strength and hardness of the weld region increased as the modified version of FSSWwas applied. Corrosion tests revealed that corrosion resistance increased as the modified method was applied.
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Behrouz Bagheri,Mahmoud Abbasi,Mohammad Givi 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.7
Friction stir spot welding (FSSW) is a solid state joining technique with a simple concept. A non-consumable rotating tool with a specially designed pin and shoulder are inserted into the sheets or plates to be joined. In this study, the effect of vibration on microstructure and thermal properties of Al5083 weldment made by FSSW using rotation speed of 1500 rpm and different dwelling times, namely 5 and 10 s, was investigated. This new method was entitled FSSVW (friction-stir-spot-vibration welding). The experimental and numerical results, obtained using Abaqus software, were compared. In this work, the Johnson–Cook hardening condition was used for modeling of deformable metals. The results showed good comparability between experimental and FEM data. Also, metallography analyses indicated that the grain size decreased and the temperature increased as FSSVW method was applied. The results showed that vibration during FSSW leads to grain size decrease of about 30–50% in the weld region.
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Behrouz Bagheri,Ali Shamsipur,Amin Abdollahzadeh,Seyyed Ehsan Mirsalehi 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.4
In this work, aluminum-copper composites reinforced with 50 nm and 250 nm SiC particles are fabricated on the interfaceof sheets by friction stir spot welding for the first time. In addition, the finite element method is used to study visual andunderstand the temperature distribution and mechanical characteristics of the composite with different nanoparticle sizes. Micro stress/strain field mainly simulated the impacts of particle size and particle distribution in the matrix. Results showedthat large reinforcing particles lead to an increase in temperature distribution and grain size in the stir zone of the jointsample. It was also concluded that the addition of finer nanoparticle size causes higher shear tensile (5.4 MPa) and Von-Mises stress (260 MPa) in the workpiece due to higher homogeneous distribution and less agglomeration in the matrix. Inaddition, the thickness of the intermetallic compound (IMCs) layer at the interface of the joint interface was analyzed as SiCparticles with different sizes are used due to higher interaction and intermixing between materials. The stress distributionand equivalent plastic strain of particles in the stir zone, with the uniform distribution of reinforcing particles for lower size(50 nm), increased.
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Mahmoud Abbasi,Behrouz Bagheri,Rasoul Keivani 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.2
Friction stir welding (FSW) as an efficient solid state joining process has numerous applications in industries. Temperature distributionanalysis through simulation not only brings the possibility to characterize the microstructure of different zones, but also enables one tosave cost and energy as optimum welding variables are obtained with less concern. In the present study, the temperature distributionduring the friction stir welding (FSW) process of AA6061-T6 was evaluated using finite element method (FEM). Since experimentalmeasurements cannot be readily made in the weld region, it is difcult to understand physics in the stir zone of the welds without simulation. Abaqus software was applied to model the parts and simulate the process of welding, while Johnson-Cook law utilized to evaluatethe effect of strain rate and generated heat. FE-results were verified by experimental results. The comparisons revealed a good compatibilitybetween the results. The effect of probe shape on temperature distribution was also studied. It was found that spherical pins result inthe highest temperatures at workpieces with respect to cylindrical and tapered pins. Additionally, it was concluded that more heat is generatedin workpieces as pin angle increases.
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