Effect of Welding Parameters on Microstructure, Thermal, and Mechanical Properties of Friction-Stir Welded Joints of AA7075-T6 Aluminum Alloy

Lotfi, Amir Hossein; Nourouzi, Salman

doi:10.1007/s11661-014-2235-z

Cited by 28 publications

(13 citation statements)

References 30 publications

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“…Low rotational speed results in insufficient flow of plasticized metal due to low frictional heat, which leads to defects such as dimples and voids. A similar observations were made by Lotfi and Nourouzi (2014) on AA7075-T6 aluminum alloy and Lakshminarayanan and Balasubramanian (2013) on AISI 409M ferritic stainless steel. When tool rotational speed was increased from 1500 rpm to 1700 rpm, fine grains formed causing an improvement in tensile strength.…”

Section: Results and Discussion Based On The Rs Modelsupporting

confidence: 81%

Tensile Properties Improvement on Friction Stir Welded Age-Hardenable Aluminum Alloys: An Evolutionary Approach using RSM based GA and SA

2016

Rev. Téc. Ing. Univ. Zulia.

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AA2024 and AA6061 aluminum alloys were fabricated using the friction stir welding technique to improve the tensile properties such as ultimate tensile strength (UTS) and tensile elongation (TE). The BoxBehnken design matrix with four significant factors-rotational speed (X(1)), welding speed (X(2)), axial load (X(3)), and pin shape (X(4)), each having three levels-was used with response surface methodology to develop a mathematical model. The experiments yielded ultimate tensile strength of 141 MPa at 12% tensile elongation. The obtained tensile properties of fabricated weld joints were low when compared to those of base materials. Several voids and pinholes were found, these being the consequence of poor tensile properties on the fabricated weld joints. Therefore, to maximize the tensile properties, two computational approaches were employed: a genetic algorithm and a simulated annealing algorithm. The main objectives of applying these computational approaches were: (1) to maximize the UTS and TE compared to the welding performance value of the experimental data and regression modeling; (2) to estimate the optimal process parameter values that must be within the obtained range of the minimum and maximum values; and (3) to evaluate the number of iterations generated by the computational approaches. The results show that use of the computational approaches resulted in significant improvement in the tensile properties. Comparing the genetic algorithm with the simulated annealing algorithm, the latter maximizes the tensile properties of fabricated AA2024 and AA6061 aluminum alloy weld joints; however, a considerable number of iterations and substantial amount of time was required to achieve a global optimal solution.

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Section: Results and Discussion Based On The Rs Modelsupporting

confidence: 81%

Tensile Properties Improvement on Friction Stir Welded Age-Hardenable Aluminum Alloys: An Evolutionary Approach using RSM based GA and SA

2016

Rev. Téc. Ing. Univ. Zulia.

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“…A lot of research has been conducted on process parameters and their effects on FSW aluminum alloys. The process parameters for welding are important for control-ling heat generation, plastic deformation, material flow, material mixing, metallurgy, strength, and reducing defects [12][13][14][15][16][17][18][19][20][21][22][23][24]. Recent studies on the optimal process parameters for aluminum welding found that rotation speed, welding speed, shoulder diameter per pin diameter ratio, tool geometry, and surface shoulder can cause increases or decreases in the strength and number of weld line defects [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Variable Neighborhood Strategy Adaptive Search for Optimal Parameters of SSM-ADC 12 Aluminum Friction Stir Welding

et al. 2021

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In this study, we present a new algorithm for finding the optimal friction stir welding parameters to maximize the tensile strength of a butt joint made of the semisolid material (SSM) ADC12 aluminum. The welding parameters were rotational speed, welding speed, tool tilt, tool pin profile, and rotational direction. The method presented is a variable neighborhood strategy adaptive search (VaNSAS) approach. The process of finding the optimal friction stir welding parameters comprises five steps: (1) identifying the type and range of friction stir parameters using a literature survey; (2) performing experiments according to (1); (3) constructing a regression model using the response surface method optimizer (RSM optimizer); (4) using VaNSAS to find the optimal parameters for the model obtained from (3); and (5) confirming the results from (4) using the parameter levels obtained from (4) to perform real experiments. The computational results revealed that the tensile strength generated from VaNSAS was 3.67% higher than the tensile strength obtained from the RSM optimizer parameters. The optimal parameters obtained from VaNSAS were a rotation speed of 2200 rpm, a welding speed of 108.34 mm/min, a tool tilt of 1.23 Deg, a tool pin profile of a hexagon, and a rotational direction of clockwise.

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“…The large η phases that are non-coherent with the aluminum matrix have little effect on the strength of the aluminum alloys [22,[25][26][27]. Besides the precipitation strengthening, the solution strengthening, fine grain strengthening, and dislocations strengthening mechanisms also make moderate contributions to the strength of the aluminum alloys [28][29][30]. Figure 9 shows the hardness distribution along the mid-thickness line of upper sheet on the cross-section of the RFSSW joint.…”

Section: Microhardness Distributionmentioning

confidence: 99%

Microstructures Evolution in Refill Friction Stir Spot Welding of Al-Zn-Mg-Cu Alloy

Zhao¹,

Dong²,

Wang³

et al. 2020

Metals

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In this study, Al-Zn-Mg-Cu alloy was refill friction spot welded, and the precipitates, dislocation, recovery, and recrystallization characteristics were focused. In the stir zone (SZ), continues dynamic recrystallization occurs under the intense plastic deformation. All the original GP (II) zones and η' precipitates dissolved into the aluminum matrix under the welding heat input, and the stable η and E precipitates remained. In the thermo-mechanically affected zone (TMAZ), high-density dislocations and subgrains boundaries can be observed. The continued dynamic recrystallization was not activated and only dynamic recovery occurs. Sub-boundaries and high-density dislocations in this zone can be observed. In this zone, the η precipitates are coarsened and dissolution is the main evolution mechanism for the GP (II) zones and η' precipitates. In the heat-affected zone (HAZ), no dislocation was induced and all the initial precipitates were coarsened under the welding heat input. The HAZ, the TMAZ, and the SZ constitute a soft region in the refill friction stir spot welding (RFSSW) joint, and the minimum value located at the interface between the HAZ and the TMAZ.

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Effect of Welding Parameters on Microstructure, Thermal, and Mechanical Properties of Friction-Stir Welded Joints of AA7075-T6 Aluminum Alloy

Cited by 28 publications

References 30 publications

Tensile Properties Improvement on Friction Stir Welded Age-Hardenable Aluminum Alloys: An Evolutionary Approach using RSM based GA and SA

Tensile Properties Improvement on Friction Stir Welded Age-Hardenable Aluminum Alloys: An Evolutionary Approach using RSM based GA and SA

Variable Neighborhood Strategy Adaptive Search for Optimal Parameters of SSM-ADC 12 Aluminum Friction Stir Welding

Microstructures Evolution in Refill Friction Stir Spot Welding of Al-Zn-Mg-Cu Alloy

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