scholarly journals Dislocation Density-Based Modeling of Dynamic Recrystallized Microstructure and Process in Friction Stir Spot Welding of AA6082

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 672
Author(s):  
Zeng Gao ◽  
Jianguang Feng ◽  
Zhenjiang Wang ◽  
Jitai Niu ◽  
Christof Sommitsch
Keyword(s):  
Grain Size ◽  
Dislocation Density ◽  
Dynamic Recrystallization ◽  
Spot Welding ◽  
Microstructural Analysis ◽  
Friction Stir Spot Welding ◽  
Stir Zone ◽  
Friction Stir ◽  
Fine Grained ◽  
Dynamic Recrystallization Behavior

This work mainly focuses on a series of microstructural analysis and predictions regarding dynamic recrystallization behavior, change in grain size, and dislocation density. Additionally, this study includes the shape prediction of the stir zone formed during friction stir spot welding. Microstructure analysis of the joint reveals that the mechanism of dynamic recrystallization in the stir zone is geometric dynamic recrystallization. A set of constitutive equations based on dislocation density is established and implemented in DEFORM-3D software to predict dynamic recrystallization during friction stir spot welding of AA6082. From the experimental and model predictions, it is observed that the original microstructure in the stir zone is completely replaced by a recrystallized fine grained microstructure. There is satisfactory agreement between the experimental grain size and the simulated results. In addition, the predicted shape of the stir zone fits quite well with the experimental shape as well.

Microstructural analysis of the stir zone of Al alloy produced by friction stir spot welding

2009 ◽  
Vol 23 (6) ◽  
pp. 403-410 ◽  
Author(s):  
Mitsuo Fujimoto ◽  
Shinji Koga ◽  
Natsumi Abe ◽  
Yutaka S. Sato ◽  
Hiroyuki Kokawa
Keyword(s):  
Spot Welding ◽  
Microstructural Analysis ◽  
Friction Stir Spot Welding ◽  
Stir Zone ◽  
Al Alloy ◽  
Friction Stir

scholarly journals Microstructural Analysis of the Stir Zone of Al Alloy Produced by Friction Stir Spot Welding

2007 ◽  
Vol 25 (4) ◽  
pp. 553-559 ◽  
Author(s):  
Mitsuo FUJIMOTO ◽  
Shinji KOGA ◽  
Natsumi ABE ◽  
Yutaka SATO S. ◽  
Hiroyuki KOKAWA
Keyword(s):  
Spot Welding ◽  
Microstructural Analysis ◽  
Friction Stir Spot Welding ◽  
Stir Zone ◽  
Al Alloy ◽  
Friction Stir

scholarly journals Microstructural Analysis of Friction Stir Butt Welded Al-Mg-Sc-Zr Alloy Heavy Gauge Sheets

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 806 ◽  
Author(s):  
Tatiana Kalashnikova ◽  
Andrey Chumaevskii ◽  
Kirill Kalashnikov ◽  
Sergei Fortuna ◽  
Evgeny Kolubaev ◽  
...  
Keyword(s):  
Base Metal ◽  
Microstructural Analysis ◽  
Metal Flow ◽  
Sheet Thickness ◽  
Stir Zone ◽  
Layer By Layer ◽  
Friction Stir ◽  
Fine Grained ◽  
Grain Size Distributions ◽  
Zr Alloy

Friction stir welding (FSW) on a heavy gauge sheet of a hereditary fine-grained Al-Mg-Sc-Zr alloy was carried out to study the specifics of plasticized metal flow and microstructural evolution in different sections and zones of the joint. It was found that the stir zone (SZ) macrostructure may contain either a single or many nugget zones depending on the metal sheet thickness and the seam length. The effect of grain kinking in a thermomechanically affected zone (TMAZ) under pressure from the stir zone metal was discovered. The stir zone metal was fine-grained but had a microhardness lower than that of the base metal, which may be explained by the overaging effect of FSW on the Al3Sc precipitates. The tensile strength of the joint was almost equal to that of the base metal (BM). The grain size distributions were obtained in different sections below the sheet surface and away from the exit hole, which allowed us to suggest the specific adhesion-assisted layer-by layer metal transfer mechanism in FSW.

Liquid Penetration Induced Cracking in Mg-Alloy Spot Welds

2008 ◽  
Vol 580-582 ◽  
pp. 409-412 ◽  
Author(s):  
M. Yamamoto ◽  
A. Gerlich ◽  
T.H. North ◽  
K. Shinozaki
Keyword(s):  
Spot Welding ◽  
Friction Stir Spot Welding ◽  
Stir Zone ◽  
Mg Alloy ◽  
Liquid Penetration ◽  
Key Factors ◽  
Spot Welds ◽  
Friction Stir ◽  
Temperature Cycles

Liquid Penetration Induced (LPI) cracking during AZ91, AZ31 and AM60 friction stir spot welding is investigated. The temperature cycles, within the stir zone and in the TMAZ region, are examined. The mechanism and the key factors determining LPI cracking in Mg-alloy friction stir spot welds are delineated.

Dynamic Recrystallization in Similar 5182 Al/Al and Dissimilar Al/Fe Friction Stir Spot Welds

2012 ◽  
Vol 715-716 ◽  
pp. 152-157
Author(s):  
Anne Laure Etter ◽  
Sandrine Bozzi ◽  
Thierry Baudin
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Dynamic Recrystallization ◽  
Spot Welding ◽  
Dynamic Recovery ◽  
Friction Stir Spot Welding ◽  
If Steel ◽  
Friction Stir ◽  
6016 Aluminum Alloy ◽  
Dynamic Grain Growth

Dynamic recrystallization mechanisms have been studied after 5182 aluminum Friction Stir Spot Welding (FSSW) and dissimilar friction stir spot welding of 6016 aluminum alloy to IF-steel using EBSD measurements. Moreover, welds have been ice quenched after welding to state on the post-dynamic microstructure evolution after the tool removal. For the Al/Al welds, fine recrystallized grains of the stir zone result from a continuous dynamically recrystallization mechanism followed by a post-dynamic recovery that reduces the low angle boundary fraction in the periphery of the pin. As far as the dissimilar Al/Fe welds are concerned, steel grains of the base metal were fragmented into sub-grains in the thermomechanically affected zone. Nevertheless, recrystallized grains of the stirred zone were about three times larger than these sub-grains. In this case, the continuously recrystallized grains undergo a post-dynamic grain-growth during friction stir welding cooling. In the upper aluminum sheet, the recrystallization mechanisms are the same as in the Al/Al welds.

Comparative Study of Spot Welding and Firiction Stir Spot Welding of Al 2024-T3

2018 ◽  
Vol 786 ◽  
pp. 104-118
Author(s):  
M.H. Fahmy ◽  
Hamed Abdel-Aleem ◽  
M.R. Elkousy ◽  
N. M. Abdel-Elraheem
Keyword(s):  
Shear Strength ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Dendritic Structure ◽  
Friction Stir Spot Welding ◽  
Stir Zone ◽  
Tensile Shear ◽  
Friction Stir ◽  
Resistance Spot ◽  
Aluminum Alloy 2024

This investigation is performed to compare the resistance spot welding (RSW) of aluminum alloy (2024-T3) with friction stir spot welding (FSSW) techniques. In this work, parameters of both resistance spot welding (RSW) and friction stir spot welding (FSSW) techniques were optimized and the optimum welding variables for both techniques were obtained. For FSSW, the tensile shear strength increased with increasing probe length, tool rotational speed and tool holding time. Tensile shear force value of RSW is about 66% of that of FSSW. This is explained by the coarse dendritic structure in resistance spot welding compared to the plastically deformed stir zone and heat affected zone in FSSW. The ratio of nugget shear strength of RSW and FSSW to base metal is about 71% and 149% respectively. The maximum hardness was obtained in stir zone at the surface of the tool. Very fine grain size of about 4 microns was obtained in stir zone followed by elongated and rotated grains in TMAZ where dynamic recrystallization did not occur.

scholarly journals Friction Stir Spot Welding-Brazing of Al and Hot-Dip Aluminized Ti Alloy with Zn Interlayer

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 922 ◽  
Author(s):  
Xingwen Zhou ◽  
Yuhua Chen ◽  
Shuhan Li ◽  
Yongde Huang ◽  
Kun Hao ◽  
...  
Keyword(s):  
Spot Welding ◽  
Friction Stir Spot Welding ◽  
Fracture Load ◽  
Stir Zone ◽  
Welding Parameters ◽  
Al Alloy ◽  
Ti Alloy ◽  
Friction Stir ◽  
2014 Al Alloy ◽  
Al Coating

Friction stir spot welding (FSSW) of Al to Ti alloys has broad applications in the aerospace and automobile industries, while its narrow joining area limits the improvement of mechanical properties of the joint. In the current study, an Al-coating was prepared on Ti6Al4V alloy by hot-dipping prior to joining, then a Zn interlayer was used during friction stir joining of as-coated Ti alloy to the 2014-Al alloy in a lap configuration to introduce a brazing zone out of the stir zone to increase the joining area. The microstructure of the joint was investigated, and the joint strength was compared with the traditional FSSW joint to confirm the advantages of this new process. Because of the increase of the joining area, the maximum fracture load of such joint is 110% higher than that of the traditional FSSW joint under the same welding parameters. The fracture load of these joints depends on the joining width, including the width of solid-state bonding region in stir zone and brazing region out of stir zone.

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