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Friction stir welding is a contact welding process that uses the heat generated by friction to fuse two different materials. This work is focused on the development of micro-friction stir welding which is carried out for very thin sectioned materials of thickness 1000[Formula: see text][Formula: see text]m or less. Friction welded butt-joints were successfully produced for 0.8[Formula: see text]mm thin AA6061 and SS304 sheets on a semi-automated vertical milling machine using a zero-pin length tool. A mild steel backing plate is used as fixture mechanism to hold the welding sheets on machine. Tool-rotational speed and Tool-travel speed are the weld-parameters examined on mechanical responses such as tensile behavior, micro-hardness and surface-roughness across the nugget-weld zone interface. The maximum tensile strength is obtained at lower weld-parameters. Tensile strength properties of AA6061-T6/SS304 joints were approximately found to be 25% lower than that of the AA6061-T6 alloy base metal. Maximum hardness value of 93HV and minimum roughness value of 2.808[Formula: see text][Formula: see text]m are observed for higher tool speeds at nugget-weld zone interface due to the formation of intermetallic phases. Microstructural behavior is studied on weld-parameters using scanning electron microscope and energy dispersive X-ray analyzer. Very thin intermetallic layers (consisting of Fe2Al5, FeAl3 and FeAl2 phases) were observed in stainless steel/aluminum interface.

Friction stir welding [FSW] is a promising technique for joining various similar and dissimilar materials with an application of frictional heat source generated by a non-consumable rotating tool for achieving high quality welds. In this article, FSW process is focused on the development of micro-friction stir welding [μFSW], which is observed on very thin sectional materials of thickness 1000 μm [1 mm] or less. The joining of precipitation-hardened aluminium alloy to pure-copper sheets of 0.8 mm thickness each were carried out on a semi-automatic vertical milling machine using a zero-pin length tool configuration. A mild steel backing plate is designed for fixture mechanism to hold the welding sheets on machine. Weld-process parameters coded for tool-rotational speed, tool-travel speed and tool-plunge depth are examined for predicting better joint characteristics. Mechanical responses such as tensile strength, yield strength, percentage-elongation and micro-hardness are recorded for better weld joints at weld-nugget zone [WNZ] interface. Microstructural features are observed on achieved mechanical responses of welded joints using scanning electron microscope [SEM] and energy dispersive X-ray [EDX] analyzer.

This work is an attempt to identify the optimum weld-process variables for micro-friction stir welding of Al6061(T6) and Cu101 sheets using multi-response optimization. The experiments were conducted according to L9 orthogonal array with selected input variables namely tool-rotational speed and tool-travel speed. The response variables considered in this study are ultimate tensile strength, micro-hardness and surface-roughness which determine the strength of the welded-joint. The multi-response optimization approach namely Technique for Order Preference by Similarity to Ideal Solution(TOPSIS) method is used to determine the optimum process variables that provides the best value among all response variables. Finally, the optimal solution shows that multi-responses of micro-friction stir welds can be improved through TOPSIS method.

The need for more efficient design has become a main concern to work with a good range for angle of attack (AOA) to reduce the stall formation. In this project, two types of NACA series airfoils i.e., symmetrical and asymmetrical profiles depending on their usage in various sectors are compared. The profile of the airfoils is imported into ANSYS Fluent from the data files. The 2D geometry of the airfoils is simulated under two different wind velocitiesi.e., at 3m/s and 15m/s respectively. The graphs are plotted for comparing coefficients of lift (CL) and drag (CD)withrespect to the angle of attack(α) for symmetrical and asymmetrical airfoils. The stall formation with change of geometry and angle of attack is also observed.