Mechanical Parameters Response on Micro-Friction Stir Welding of AA6061 and SS304 Sheets

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.