Friction stir welding (FSW) can be defined as a green technology, because the consumption of energy during this process is less than other welding methods. In addition, during the process there is no gas, filler material or other consumables. It should be noted that, complex Curved shapes are now commonly used in different industries in a bid to have lightweight structures. According to the above-mentioned descriptions, several investigations into the potential benefits of adopting Friction Stir Welding (FSW) in the production and joining different materials are being undertaken. The work presented in this paper is focused on thermal behavior of the Curved FSW and its benefits for the green technology. Due to the robust nature of FSW process aluminum 6061-T6 alloy has been selected as the welding material. The results of the study showed that, the total peak temperature value of 300° C happened at time, t = 3 s at the plunge stage (outside of the welding seam). Meanwhile, at the dwell stage (between t = 3 s to t = 5 s), there is a stable situation in the amount of the generated heat from the plastic deformation as well as the contact shear stress at the tool-workpiece contact interfaces, thus the interfacial temperature is found to be stable. By the end of the dwelling step, the total generated heat is stable to the maximum value of 300° C. At the step time of t = 12. 8 s, the temperature is distributed asymmetrically across the workpiece until the time step of 19. 6 s which at this point the asymmetric contour expanded in the stir zone.

The high-level radioactive waste will be encapsulated in copper canisters and stored in a deep repository. High power electron beam welding was the only viable method available at that time for welding thick section copper. In recent years, friction stir welding has been replaced with electron beam welding because of the promotion in mechanical properties and corrosion resistance of copper canisters. FSW is used in solid state, therefore residual stresses produced in the weld is less than that of other welding processes which are performed in the molten state. To obtain optimum rotational speed, FSW was carried out in copper plates with a thickness of 4 mm at a constant speed of 25 mm/minute. The temperature distribution indicated a severe increasing of temperature upon increasing the rotational speed from 900 to 1200 rpm. Also, analysis of the metallographic images showed that the grain size in the nugget zone increases by increasing the rotational speed. Vickers hardness test was conducted on the welded samples and the maximum hardness was obtained at a rotational speed of 900 rpm. Results of tensile tests and their comparison with those of the base metal showed that the maximum strength and minimum elongation are achieved at the same rotational speed.

This study conducts an experimental investigation to explore the impact of the traverse speed of a tool on the tensile strength and micro-structural peculiarities of joints attained during friction stir welding of Cu alloy namely CDA 101 at plates. In this process, other parameters including spinning speed of tool (1100 rpm) and downward force (6 kN) were kept constant. A tool with a cylindrical tapered pin geometry was made to traverse at varying speeds, from 20 mm/min to 45 mm/min. It was observed that the CDA 101 joints fabricated at 20 mm/min were entirely free of flaws, while the joints fabricated at other traverse speeds of the tool were featured several weld flaws. Grains in the center of the stir zone of the joints obtained at 20 mm/min were uniformly distributed and homogeneous due to the significant volume of frictional heat and sufficient stirring force. The highest tensile strength of 200. 65 MPa (nearly 85. 38% of base metal) was exhibited by the joint attained at 20 mm/min.

In the friction stir welding process, preferred joint property is vastly reliant on the selection of optimal welding conditions. The present study aims to use the Taguchi technique to , nd the optimal process conditions for achieving superior Ultimate Tensile Strength (UTS) in friction stir welded Aluminum Matrix Composite (AMC) joints. AMCs reinforced with rutile particles which have a potential application in the aerospace, automotive, and marine industries are used in the present work. Taguchi parametric design technique was used to identify the effect of rotational speed, tool traverse speed, and tool geometry on joint strength. Taguchi approach confined the optimum level of process variables and these variables were optimized. The investigation showed that the parameters within the selected value range will seriously affect the output. The predicted value of the output response was 155. 48 MPa, which was validated by further experiments using the optimum process variables. Analysis Of Variance (ANOVA) results indicated that the UTS of the composite joint is mainly affected by the tool traverse speed followed by rotational speed, and tool geometry. The microstructural study unveiled that grain size is dependent on process variables and , finer grains offer better joint properties.

Considering the dynamics of geometry and the matter fields, dynamical equations of geometry and the matter fields are re-derived. The solutions of these equations are studied. We focus on a charged particle and explain the axiomatic approach to drive the electromagnetic self-force on its motion, then the energy conservation is considered. A new mathematical concept, which is introduced in axiomatic approach in general, is discussed.