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Metallic Foil Friction Stir Welding (MFFSW) was newly developed from the Friction Stir Welding (FSW) technique. Magnesium (Mg) alloys were the most trending alloys in the aerospace, automobile, and biomedical industries. This study aims to investigate the variation in mechanical, corrosive, microstructural, and fractographic properties of MFFSW as a process innovation when compared with FSW. The metallic foil of pure manganese (Mn) with a thickness of 500 μm was inserted between two AZ61 Mg alloys. The tensile strength, impact strength, and hardness were noted as mechanical properties of the output. Potentiodynamic corrosion tests were performed to reveal the corrosion properties. An optical microscope was used to examine a distinct transverse section of the weld. Fractography tests with scanning electron microscopic analysis were conducted on destructive tensile specimens. The ultimate tensile strength, impact energy, yield strength, and microhardness increased to 16%, 32%, 12%, and 19.17%, respectively, compared to FSW. MMFSW shows a lower elongation of up to 33% than FSW. MMFSW (9.61 mm/A) shows a lower corrosion rate than FSW (11.02 mm/A), which employs improved corrosion properties. Optical microscopy images of the stir zone in both MFFSW and FSW revealed that adding a Mn alloying element improved grain growth uniformity and eliminated unexpected grain growth patterns. Hence, the experiment's conclusion shows that MFFSW has the edge over FSW for mechanical and corrosion properties. Thus, the Mn strip improves the properties of MFFSW. [ABSTRACT FROM AUTHOR]

In engineering applications, such as automobile, marine, aerospace, and railway, lightweight alloys of aluminum (Al) and magnesium (Mg) ensure design fitness for fuel economy, better efficiency, and overall cost reduction. Friction stir welding (FSW) for joining dissimilar materials has been considered better than the conventional fusion welding process because of metallurgical concerns. In this study, dissimilar joints were made between the AA6061 (A), AZ31B (B), and AZ91D (C) combinations based on the varying advancing side (AS) and retreating side (RS). The dissimilar joints prepared by the FSW process were further characterized by tensile testing, impact testing, corrosion testing, fracture, and statistical and cost analysis. The results revealed a maximum tensile strength of 192.39 MPa in AZ91 and AZ31B, maximum yield strength of 134.38 MPa in a combination of AA6061 and AZ91, maximum hardness of 114 Hv in AA6061 and AZ31B, and lowest corrosion rate of 7.03 mV/A in AA6061 and AZ31B. The results of the properties were supported by photomicrographic fracture analysis by scanning electron microscopy (SEM) observations. Further, the performance of dissimilar joints was statistically analyzed and prioritized for preference by similarity to the ideal solution (TOPSIS) method. [ABSTRACT FROM AUTHOR]