Effect of Processing Parameters on Strength and Corrosion Resistance of Friction Stir-Welded AA6082

Abstract

The friction stir welding method is increasingly attracting interest in the railway sector due to its environmental friendliness, low cost, and ease of producing high-quality joints. Using aluminum alloys reduces the weight of structures, increasing their payload and reducing fuel consumption and running costs. The following paper presents studies on the microstructure, strength, and corrosion resistance of AA6082 aluminum alloy sheets joined via friction stir welding. The sheets were joined by employing two different traverse speeds (200 and 250 mm/min), two different rotational speeds (1000 and 1250 rpm), and two different tool tilt angles (0° and 2°). It was observed that the use of the inclined tool provides finer microstructure in the nugget zone, higher value of microhardness, and better corrosion resistance, compared to the tilt angle equal to 0°. By increasing the value of revolutionary pitch, finer grains are observed in the nugget zone and the measured hardness is higher. It was also observed that the change in process parameters strongly influences the radius of the nugget zone and the potentiodynamic properties of the friction stir-welded material. The joints produced with the tool tilt angle equal to 2°, the tool traverse speed of 200 mm/min, and its rotational speed of 1250 rpm revealed the highest hardness in the nugget zone (about 92% of the base material). Moreover, the finest grain size in the nugget with the average value of 9.8 ± 1.5 µm was found. The lowest corrosion current density equal to 16.029 µA × cm−2 was noted for the sample with the highest strength, which also provides its good corrosion resistance.

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

“…Due to the different behaviors of these alloys under deformation and temperature, differences in the hardness profile on the advancing and retreating sides can be observed. Analyzing the hardness profile from the side of the AA6060 alloy to the center of the joint, the typical shape of the hardness profile for FSW joints of 6xxx-T6 series aluminum alloys is maintained, characterized by a minimum of hardness in the heat-affected zone [26,27]. Softening observed in the heat-affected zone on the side of AA6060-T6 is an effect of precipitate coarsening and dissolution, due to sufficient heat input.…”

Effect of post-weld heat treatment on AA6351 friction stir welds

“…AA6351 is an aluminum alloy that has been developed as a high-strength material with good corrosion resistance. This alloy contains silicon, magnesium, and manganese as its main alloying elements, and often used in applications where high strength and good corrosion resistance are required, such as in the construction of aircraft and aerospace components, marine applications as structural components [1][2][3][4].…”

Influence of Process Parameters on the Mechanical Properties and Corrosion Resistance of Dissimilar Friction Stir Welded Joints of AA2024-O and AA6061-O Aluminum Alloys

“…Laska et al observed in friction stir welded joints of AA6082 alloys that the best corrosion behavior in NaCl 3.5% solution was obtained with the highest revolutionary pitch (between 6.0 and 6.5 rev•mm −1 ) [45]. Souza et al studied localized corrosion resistance in friction stir welded joints of AA2198-T8 alloys.…”