Investigation of microstructure and mechanical characteristic of underwater friction stir welding for Aluminum 6061 alloy – Silicon carbide (SiC) metal matrix composite

Abstract

Demand for metal matrix composites (MMCs) is expected to increase in these applications, such as ‎in the aerospace and automotive sectors. Adequate joining techniques, which are important for ‎structural materials, have not yet been developed for Metal Matrix Composite (MMCs), however. ‎This work aimed to demonstrate the feasibility of ‎friction stir welding (FSW) and ‎underwater friction stir welding (UFSW) for joining Al 6061/5, Al 6061/10, and Al ‎‎6061/18 wt. %SiC composites have been produced by utilizing reinforce stir casting technique. Two ‎rotational ‎speeds,1000and 1800 rpm, and traverse speed 10mm \ min were examined. Specimen ‎composite plates 10 mm thick have been successfully welded by FSW. For FSW and UFSW, a tool ‎made of high-speed steel (HSS) with a conical pin shape was used. The result revealed that the ‎ultimate tensile strength of the welded joint by FSW and UFSW at rotation speed 1800 rpm for (Al ‎‎6061/18 wt. ‎‎% SiC composites) was 195 MPa and 230 MPa respectively. The ultimate ‎tensile ‎strength of the welded joint by FSW and UFSW (Al 6061/18 wt.% SiCe composites) was 165 MPa ‎and 180 MPa at rotation speed ‎‎1000 rpm respectively. The microstructural assessment showed that due ‎to larger grain sizes at FSW and UFSW, most of the fractures are located in the thermal ‎mechanically affected zone (TMAZ) adjacent to the weld nugget zone (WNZ). It is observed that in ‎failure, most of the joints show ductile features. As the volume fraction of SiC (18 wt.%) increases, ‎the friction stir welded and underwater friction stir welded efficiency decreases.

Underwater friction-stir welding of a stir-cast AA6061-SiC metal matrix composite: optimization of the process parameters, microstructural characterization, and mechanical properties

“…The metallographic specimens were made from 6061 AMC and 6061 AMC that had been welded together. According to ASTM E8-04, the standard tensile specimens were sliced perpendicular to the joint line and created from all specimens [18]. TS has been prepared by the length of a gauge of 57.2 mm, the width of a gauge of 12.2 mm, and a thickness of 10 mm.…”

Implementation of hybrid RSM-GA optimization techniques in underwater friction stir welding

“…This is due to insufficient material flow and lack of bonding between welded plates at low shoulder diameter. The larger heat generation at higher shoulder diameter causes heat dissipation to the workpiece which forms coarse grain at the weld zone and decreases the UTS [21]. Tool rotational speed influences the heat generation and deformation of material as it has a certain role in stirring the base metal to produce high strength of weld joints.…”

“…Few researchers have used the optimization technique in the friction stir welding field but very little in case of UWFSW. The ANFIS Integrated Hybrid Methods are provided in this study for successfully modeling the UWFSW parameters with performance reaction values [20][21][22]. The RSM-GA Integrated Hybrid Methods are suggested in this research for modeling the UWFSW parameters.…”