Experimental studies on friction stir welding of aluminium alloy 5083 and prediction of temperature distribution using arbitrary Lagrangian–Eulerian-based finite element method

The present work focused on welding aluminium alloy 5083 using the friction stir welding process. Suitable welding process parameters were identified to fabricate a defect-free butt joint with a tool rotational speed of 1600 rpm, traverse speed of 20 mm/min and tilt angle of 3°. The microstructure at the nugget zone, thermo mechanically affected zone, heat-affected zone and base metal zone are examined. Mechanical properties of the weldment exhibited promising results with an average joint efficiency and hardness of 75.70% and 94.0 ± 5.0 vickers hardness, respectively. Fractography revealed ductile mode of failure in base and weld metal tensile samples. Furthermore, a 3D thermomechanical finite element model was utilized to simulate the friction stir welding process using the selected process parameters. Arbitrary Lagrangian–Eulerian-based model aided in predicting residual stress distributions and thermal history during the friction stir welding process.

EFFECT OF TOOL PIN PROFILES OVER SQUARE WAVE TOOL PATH PATTERN ON FRICTION STIR WELDING OF AA6061-CU DISSIMILAR ALLOYS

In this present work friction stir welding of Al6061-annealed pure copper dissimilar metals with square wave pattern tool pin movementwas investigated. The aim of this experiment is to identify the significance square wave tool movement on friction stir welding process along with three different tool pin profiles. Different tool pin profiles of square, round and hexaspiral shapes were selected and their significant outcomes were unveiled. Friction stir welding process parameters of 1500 and 2000rpm & tool pin movement step size of 1.0mm and 2.0mm & weaving rate of 100mm/min and 150mm/min were selected. The advantages of tool movement pattern and tool pin profile shape wereexamined by mechanical testing, microstructure analysis. The mechanical results were showed that process parameter of 1500 rpm, 1.0mm step size, weldingrate of 150mm/min and square tool pin profile combination gives better mechanical properties. Micro structural results unveiled achievement of better grain refinement and uniform dispersion of micro constituents by implementation of square wave tool pin movement pattern along with square tool pin profile.The EDAX report confirms that the weld nugget contains both aluminum and copper as equal percentage, which indicates fine mixing of two parent metals.

A modified version of friction stir welding process of aluminum alloys: Analyzing the thermal treatment and wear behavior

In this article, the effect of vibration and cooling media on the friction stir welding of 5083Al alloy is investigated. The vibration was introduced by the motor into the fixture inserted under the workpiece while a cooling media (water and lubrication oil) flowed into a canal in the fixture beneath the weld path. A constant rotation speed of 1250 r/min and a traveling speed of 90 mm/min were used for all the welding conditions. The thermal analysis measured by several thermocouples indicated that friction stir vibration welding (FSVW) provided maximum temperature distribution in the workpiece, while friction stir welding with the water cooling exhibited the lowest temperature value. The microstructure observations were conducted by optical microscope, scanning electron microscopy, and transmission electron microscopy. The results indicated substantial grain refinement when vibration and water cooling were simultaneously applied during the friction stir welding process. The hardness values increased from 50 to around 78 (Hv) for friction stir welding and FSVW with water systems, respectively. The joint efficiency (the ratio of the joint strength to the base metal strength) of the joint fabricated by FSVW with water cooling was around 87%, while this quantity was about 66% for the friction stir welding joint. Fracture analysis indicated more ductile behaviors for the samples fabricated by FSVW with the coolant systems. Furthermore, the joint fabricated by FSVW with water cooling exhibited the best wear resistance among all the samples in a pin-on-disk wear test.