Effect of tool dimensions and parameters on the microstructure of friction stir welded aluminum 7449 alloy of various thicknesses

Martinez, N.; Kumar, N.; Mishra, Rajiv S.; Doherty, Kevin J.

doi:10.1016/j.msea.2016.12.077

Cited by 36 publications

(10 citation statements)

References 20 publications

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“…During the FSP/FSW, the material experiences intense plastic deformation at elevated temperatures, leading to the formation of a stir zone (SZ) with recrystallised and fine-grained microstructure [4]. The microstructure and the mechanical properties of SZ are controlled by the processing parameters including rotational speed, traverse speed and tool geometry, and a great number of works have been done to optimise these parameters [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Effects of friction-stir processing with water cooling on the properties of an Al–Zn–Mg–Cu Alloy

Chen

Jiang

Ding

et al. 2018

Materials Science and Technology

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An Al–Zn–Mg–Cu (Al-7B04) aluminium alloy in two conditions, i.e. with an artificial aging (7B04-AA) temper and with an annealing (7B04-O) temper, was friction-stir processed using water cooling, and the microstructure and the mechanical properties of the stir zone (SZ) were investigated. Compared with the samples subjected to air cooling, the SZs of water-cooled samples were strengthened, and the degree of strengthening depended on the initial base metal temper. For friction-stir-processed material after an 7B04-O temper, the efficiency of strengthening was relatively high due not only to the refinement of grains and strengthening precipitates but also due to the high solution level in the SZ. In contrast, the slight strengthening of friction-stir-processed 7B04-AA resulted solely from grain refinement.

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Section: Introductionmentioning

confidence: 99%

Effects of friction-stir processing with water cooling on the properties of an Al–Zn–Mg–Cu Alloy

Chen

Jiang

Ding

et al. 2018

Materials Science and Technology

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“…Therefore, a decrease in the deformation temperature and strain rate generally occurred from the top to the bottom of the stir zone [ 17 , 18 ]. This gradient of the deformation temperature and strain rate resulted in differences in grain size, dislocation density, recrystallization, and precipitation in different regions of the stir zone [ 19 , 20 , 21 , 22 , 23 ]. Additionally, during the deformation process, the shear deformation modes of the shoulder-driven and pin-driven are different, resulting in various texture components in the stir zone [ 24 , 25 , 26 ].…”

Section: Introductionmentioning

confidence: 99%

Restirring and Reheating Effects on Microstructural Evolution of Al–Zn–Mg–Cu Alloy during Underwater Friction Stir Additive Manufacturing

Wei

et al. 2022

Materials

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Friction stir additive manufacturing (FSAM) can be potentially used for fabricating high-performance components owing to its advantages of solid-state processing. However, the inhomogeneous microstructures and mechanical properties of the build attributed to the complex process involving restirring and reheating deserve attention. This study is based on the previous research of the underwater FSAMed 7A04 aluminum alloy and adopts a quasi in situ experimental method, i.e., after each pass of the underwater FSAM, samples were taken from the build for microstructural observation to investigate the restirring and reheating effects on microstructural evolution during the underwater FSAM. Fine-grain microstructures were formed in the stir zone during the single-pass underwater FSAM. After restirring, the grain size at the bottom of the overlapping region decreased from 1.97 to 0.87 μm, the recrystallization degree reduced from 74.0% to 29.8%, and the initial random texture transformed into a strong shear texture composed of the C {110}<11¯0>. After reheating, static recrystallization occurred in the regions close to the new additive zones, increasing the grain size and recrystallization degree. This study not only revealed the microstructural evolution during the underwater FSAM but also provided a guideline for further optimization of the mechanical properties of the Al–Zn–Mg–Cu alloy build.

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“…In this relation, the constant K = 0.65 -0.75, and the exponent α = 0.04 -0.06. [41][42][43][44][45][46], numerical modeling has been used to study the peak temperature affected by process parameters. Although the "Coupled Eulerian-Lagrangian Solver" [47]; due to its greater solution accuracy has attracted attention, but the modeling process using this technique is time consuming [48].…”

Section: Introductionmentioning

confidence: 99%

Numerical and experimental investigation of defects formation during friction stir processing on AZ91

et al. 2021

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The heat generated during friction stir processing greatly affects defects formation in the processed zone of workpieces. In this paper, numerical modeling of this process is performed to determine the influence of tool rotational and traverse speeds and hence their ratio on the thermal distribution attained during the process. The aim is to produce defect-free processed samples by selecting adequate tool speeds. The mechanisms of defects formation depending on the peak temperature are also investigated. Experiments to verify the simulation results were conducted with the same process parameters. Several traverse speeds of 20, 40, 60, and 80 mm/min and rotational speeds of 700, 1000, 1200, and 2000 rpm were used during modeling and conducting the experiments. From the numerical and experimental results, it was found that; the high-speed processing conditions (low-generated heat) can produce defects such as tunnels and grooves, and the low-speed processing conditions (high-generated heat) can cause defects such as flashes. The experimental results show that during friction stir processing with the rotational speed of 1200 rpm and the traverse speed of 60 mm/min (speed ratio of 20), no macro defects in the processed zone were observed. According to the numerical results, the peak temperature during friction stir processing with these speeds was 475 °C. At this temperature, the material softened, the structure finely equiaxed and no large scale melting zone appeared in the processed zone. The developed model can be useful to investigate the occurrence of defects associated with different tool rotational and traverse speeds. Graphic abstract

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Effect of tool dimensions and parameters on the microstructure of friction stir welded aluminum 7449 alloy of various thicknesses

Cited by 36 publications

References 20 publications

Effects of friction-stir processing with water cooling on the properties of an Al–Zn–Mg–Cu Alloy

Effects of friction-stir processing with water cooling on the properties of an Al–Zn–Mg–Cu Alloy

Restirring and Reheating Effects on Microstructural Evolution of Al–Zn–Mg–Cu Alloy during Underwater Friction Stir Additive Manufacturing

Numerical and experimental investigation of defects formation during friction stir processing on AZ91

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