Influence of the Tool Rotational Speed on Physical and Chemical Properties of Dissimilar Friction-Stir-Welded AA5083/AA6060 Joints

Abstract

Aluminum alloys have been successfully used in the railroad and automotive industries because of their potential to significantly reduce component weights, and their good mechanical and anti-corrosion properties. Problems with joining aluminum alloys are characterized by low weldability, which influences the need for studies focused on unconventional methods. The environmentally friendly and low-cost friction-stir-welding method enables the material to be joined without melting. In the following study, dissimilar butt joints were produced from AA5083 and AA6060 alloys. A constant tool traverse speed of 100 mm/min and a tool tilt angle of 2º were used, combined with tool rotational speeds of 800, 1000 and 1200 RPM. It was revealed that as the tool speed increases, the hardness in the weld nugget zone increases, due to higher heat input and more effective recrystallization. The highest hardness of the weld nugget zone was observed for the weld that was produced with the highest tool rotational speed, and was equal to 1.07 GPa, compared to the hardness of both parent materials of 0.75 and 1.15 GPa for AA5083 and AA6060, respectively. Increasing the heat input also decreased the hardness of the heat-affected zone, where recrystallization was not observed. The lowest density of dislocations with the highest mobility was observed in the heat-affected zone on the AA6060 side, which also contributed to the reduction in strength in this zone. The produced welds exhibited corrosion resistance between both parent materials, with the lowest corrosion current density being 6.935 ± 0.199 µA·cm–2 for the weld that was produced at a tool speed of 1200 RPM.

Effect of Process Parameters on Friction Stir Welded Joints between Dissimilar Aluminum Alloys: A Review

“…Several studies on FSW involve dissimilar aluminum alloys [31,131]. Ghaffarpour et al [132] join dissimilar aluminum alloys of 5083-H12 in the retreating side and 6061-T6 in the advancing side, changing the rotational speed (i.e., 700, 1600, 2500 rpm) in combination, respectively, with the pin diameter (i.e., 2, 3, 4 mm), the shoulder diameter (i.e., 10, 12, 14 mm), and the traverse speed (i.e., 25, 212.5, 400 mm/min).…”

Influence of tool pin profile on the mechanical strength and surface roughness of AA6061-T6 overlap joint friction stir welding

“…This study revealed that when spindle speed and feed rate increase simultaneously, agitation offers less frontal resistance due to uniform heat distribution during processing. The increase in spindle speed and feed rate will directly increase the heat generation, thus causing smooth material flow [34][35]. Due to this process, the softening material under the tool shoulder caused by the frictional heat after plunging increases the plasticisation of the material, thus helping the material to mix and stir during the joining process.…”

Assessing the role of friction stir welding tool shoulder profile and parameters on mechanical performance of Al5083 weld joints pre- and post-corrosion exposure

“…Particularly, welding of Al alloys by FSW can be widely seen in the scientific literature [11][12][13]. Different Al alloys which belong to magnesium, aluminum and copper systems were also successfully joined with Al5083 alloy by FSW [14][15][16][17][18]. In FSW, tool design which is governed by the selection of tool dimensions including shoulder to pin diameter ratio, dimensions of pin, shoulder profile, pin profile etc influence the success of the welding process [19].…”