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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:The paper presents the results of testing the wear of the tool (pull broach) and a gear wheel splineway surface roughness after the friction node of pull broach/gear wheel (CuSn12Ni2) had been lubricated with metal machining oil and the same oil modified with chemically active exploitation additive. To designate the influence of modifying metal machining oil by the exploitation additive on the lubricating properties, anti-wear and antiseizure indicators have been appointed. Exploitation tests have proved purposefulness of modifying metal machining oil. Modification of the lubricant has contributed to reduction of the wear of the tools -pull broaches and to reduction of roughness of the splineway surfaces.

The paper presents results of tribological properties of the kinematic pair: X210Cr12 steel / CuSn10 bronze, lubricated within the friction process by engine oil SAE 20W/40, and by the same lubricant modified by chemical exploitation preparation. Research of tribological properties were carried out using the tester T-05 (type tester roll - block). Tests have been carried out in two stages. In the first order - friction force, wear of the kinematic pair and the temperature of the friction area have been determined. The objective of the second phase was to micro roentgen spectral analysis of the surface friction zone. On the basis of these studies, the analysis of the elemental composition of the surface layer in the track wear have been made. The modification purposefulness of lubricant SAE 20W/40 by chemical exploitation preparation has been shown.