The effect of heat generated on mechanical properties of friction stir welded aluminum alloys

Bocchi, Sara; D’Urso, Gianluca Danilo; Giardini, Claudio

doi:10.1007/s00170-020-06462-9

Cited by 17 publications

(17 citation statements)

References 25 publications

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“…Together these changes radically increase the tensile strength extending the UTS to ~470 MPa. This is ~90% of that of the base metal (UTS = 521 MPa), comparing favorably with the strength of the solid state friction stir welded joints 28,29 .…”

Section: A Hybrid Welding Techniquementioning

confidence: 65%

Inhibiting weld cracking in high-strength aluminium alloys

Guo

et al. 2022

Nat Commun

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Cracking from a fine equiaxed zone (FQZ), often just tens of microns across, plagues the welding of 7000 series aluminum alloys. Using a multiscale correlative methodology, from the millimeter scale to the nanoscale, we shed light on the strengthening mechanisms and the resulting intergranular failure at the FQZ. We show that intergranular AlCuMg phases give rise to cracking by micro-void nucleation and subsequent link-up due to the plastic incompatibility between the hard phases and soft (low precipitate density) grain interiors in the FQZ. To mitigate this, we propose a hybrid welding strategy exploiting laser beam oscillation and a pulsed magnetic field. This achieves a wavy and interrupted FQZ along with a higher precipitate density, thereby considerably increasing tensile strength over conventionally hybrid welded butt joints, and even friction stir welds.

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Section: A Hybrid Welding Techniquementioning

confidence: 65%

Inhibiting weld cracking in high-strength aluminium alloys

Guo

et al. 2022

Nat Commun

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“…In this welding, high-strength recrystallised metal structure weld joints are formed without cracking defects as the entire joining process is carried out above the recrystalisation temperature and below the melting point [1]. On the other hand, when the process is carried out in a temperature lower than the recrystallisation temperature, it results in defects like voids and tunnels in the stir zone [2], while higher process temperature leads to other defects, such as pores and ashes [2]. is indicates that the process parameters should be selected to induce optimum heat supply to ensure the entire joining process to be carried out in the temperature range, which produces a defect-free weld joint.…”

Section: Introductionmentioning

confidence: 99%

Heat Index Based Optimisation of Primary Process Parameters in Friction Stir Welding on Light Weight Materials

Leon

Manikandan

Santhanakrishnan

et al. 2022

Advances in Materials Science and Engineering

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In friction stir welding, tool shoulder diameter and its rotational speed are the major influencing parameters than others. A simple novel correlation is proposed to select the optimum range of tool shoulder diameter with respect to the chosen rotational speed and vice versa. The conditions to apply derived correlation were defined through process heat index number as the joint efficiency in the friction stir welding depends on the effective heat supply to the volume of material deformed in the stir zone. Weld speed is the key parameter through which generated heat can be regulated towards optimum heat supply to attain defect-free weld in the stir zone. Effective heat input also has obvious effect on grain growth and corresponding property eradication in the heat affected zone. The experimental study was carried out on AA2024-T3 plates to understand the effect of process heat index on the prescribed optimum range of tool shoulder and rotational speed defined in the correlation. Eventually, a novel relationship was attained between the first order process influencing parameters to deliver maximum joint efficiency.

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“…One example is water cooling, which reduces and controls the temperature of the joints, especially for highly conductive materials (e.g., aluminium alloys) [29,30]. A study by Bocchi et al [30] shows that water cooling increases the hardness rate in the heat affected zone (HAZ) and thermo-mechanically affected zone (TMAZ) but also decreases the elongation of the joints. On the other hand, some materials need the opposite treatment to cooling as the joint can only be produced at high temperature values.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Tool Shape and Process Parameters on the Mechanical Properties of AW-3004 Aluminium Alloy Friction Stir Welded Joints

2021

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The purpose of the following study was to compare the effect of the shape of a tool on the joint and to obtain the values of Friction Stir Welding (FSW) parameters that provide the best possible joint quality. The material used was an aluminium alloy, EN AW-3004 (AlMn1Mg1). To the authors’ best knowledge, no investigations of this alloy during FSW have been presented earlier. Five butt joints were made with a self-developed, cylindrical, and tapered threaded tool with a rotational speed of 475 rpm. In order to compare the welding parameters, two more joints with a rotational speed of 475 rpm and seven joints with a welding speed of 300 mm/min with the use of a cylindrical threaded pin were performed. This involved a visual inspection as well as a tensile strength test of the welded joints. It was observed that the value of the material outflow for the joints made with the cylindrical threaded pin was higher than it was for the joints made with the tapered threaded pin. However, welding defects in the form of voids appeared in the joints made with the tapered threaded tool. The use of the cylindrical tool resulted in higher values for about 37% of mechanical properties compared with the highest result for the tapered threaded joint. As far as the parameters were concerned, it was concluded that most of the specimens were properly joined for a rotational speed of 475 rpm. In the joints made with a welding speed of 300 mm/min, the material was not stirred properly. The best joint quality was given for a rotational speed of 475 rpm as well as a variety of welding speed values between 150 and 475 mm/min.

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The effect of heat generated on mechanical properties of friction stir welded aluminum alloys

Cited by 17 publications

References 25 publications

Inhibiting weld cracking in high-strength aluminium alloys

Inhibiting weld cracking in high-strength aluminium alloys

Heat Index Based Optimisation of Primary Process Parameters in Friction Stir Welding on Light Weight Materials

The Influence of Tool Shape and Process Parameters on the Mechanical Properties of AW-3004 Aluminium Alloy Friction Stir Welded Joints

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