Effect of welding parameters on mechanical and microstructural properties of dissimilar AA6082–AA2024 joints produced by friction stir welding
TL;DR: In this paper, the effect of processing parameters on the mechanical and microstructural properties of dissimilar AA6082-AA2024 joints produced by friction stir welding was analyzed.
About: This article is published in Materials & Design.The article was published on 2009-03-01. It has received 257 citations till now. The article focuses on the topics: Welding & Friction stir welding.
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TL;DR: In this paper, the microstructures and mechanical properties of friction stir welded Al-alloys existing in the open literature are discussed in detail in order to highlight the correlations between weld parameters used during FSW and the micro-structures evolved in the weld region and thus mechanical properties.
Abstract: The diversity and never-ending desire for a better life standard result in a continuous development of the existing manufacturing technologies. In line with these developments in the existing production technologies the demand for more complex products increases, which also stimulates new approaches in production routes of such products, e.g., novel welding procedures. For instance, the friction stir welding (FSW) technology, developed for joining difficult-to-weld Al-alloys, has been implemented by industry in manufacturing of several products. There are also numerous attempts to apply this method to other materials beyond Al-alloys. However, the process has not yet been implemented by industry for joining these materials with the exception of some limited applications. The microstructures and mechanical properties of friction stir welded Al-alloys existing in the open literature will be discussed in detail in this review. The correlations between weld parameters used during FSW and the microstructures evolved in the weld region and thus mechanical properties of the joints produced will be highlighted. However, the modeling studies, material flow, texture formation and developments in tool design are out of the scope of this work as well as the other variants of this technology, such as friction stir spot welding (FSSW).
325 citations
TL;DR: In this article, the optimal process parameters were determined with reference to tensile strength of the joint and confirmed by conducting the confirmation run using the predicted optimal parameters using optimum parameters, which were optimized using Taguchi L16 orthogonal design of experiments.
255 citations
TL;DR: In this paper, an integrated modeling framework for friction stir welding of 6xxx series Al alloys has been established and applied to the 6005A and 6056 alloys.
234 citations
TL;DR: In this article, an Artificial Neural Network (ANN) model was developed to simulate the correlation between the friction stir welding parameters and mechanical properties, and the model was employed to predict the ultimate tensile strength and hardness of Butt joint of AA7075-O to AA5083-O aluminium alloys.
163 citations
Additional excerpts
...Several different dissimilar aluminium alloy combinations have been successfully friction stir welded with reasonably good joint efficiencies [5–12]....
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30 Aug 2009-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, an experimental and numerical investigation on the lap joining of AA2198-T4 aluminum alloy blanks by FSW is presented, in particular the joints strength and metallurgical properties are investigated by varying the joint configuration and the tool geometry and rotational speed.
Abstract: Aluminum alloys are widely used in the aircraft industries even if such materials present lower ductility with respect to steels, anisotropy phenomena and, more important, they are often “difficult” to be welded or even “non-weldable”. In the last years the friction stir welding process (FSW) was proposed and applied in order to get good mechanical and technological performances of the joints. In this paper, an experimental and numerical investigation on the lap joining of AA2198-T4 aluminum alloy blanks by FSW is presented. In particular the joints strength and metallurgical properties are investigated by varying the joint configuration and the tool geometry and rotational speed. It is found that the use of cylindrical–conical pin tools and the correct choice of the relative sheet positioning increase the welded nugget extension and integrity improving the mechanical performances of the obtained joints.
159 citations
References
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30 Mar 2007TL;DR: Friction stir welding (FSW) is a relatively new solid-state joining process that is used to join high-strength aerospace aluminum alloys and other metallic alloys that are hard to weld by conventional fusion welding as discussed by the authors.
Abstract: Friction stir welding (FSW) is a relatively new solid-state joining process. This joining technique is energy efficient, environment friendly, and versatile. In particular, it can be used to join high-strength aerospace aluminum alloys and other metallic alloys that are hard to weld by conventional fusion welding. FSW is considered to be the most significant development in metal joining in a decade. Recently, friction stir processing (FSP) was developed for microstructural modification of metallic materials. In this review article, the current state of understanding and development of the FSW and FSP are addressed. Particular emphasis has been given to: (a) mechanisms responsible for the formation of welds and microstructural refinement, and (b) effects of FSW/FSP parameters on resultant microstructure and final mechanical properties. While the bulk of the information is related to aluminum alloys, important results are now available for other metals and alloys. At this stage, the technology diffusion has significantly outpaced the fundamental understanding of microstructural evolution and microstructure–property relationships.
4,750 citations
TL;DR: In this article, the microstructural changes effected by friction stir welding of 7075 Al. were evaluated and the authors concluded that friction-stir welding has the potential to avoid significant changes in microstructure and mechanical properties.
819 citations
TL;DR: In this paper, the effects of friction-stir welded aluminum alloy 7050 in a T7451 temper to investigate the effects on the microstructure and mechanical properties were investigated.
Abstract: Aluminum alloy 7050 was friction-stir welded (FSW) in a T7451 temper to investigate the effects on the microstructure and mechanical properties. Results are discussed for the as-welded condition (as-FSW) and for a postweld heat-treated condition consisting of 121 °C for 24 hours (as-FSW + T6). Optical microscopy and transmission electron microscopy (TEM) examination of the weld-nugget region show that the FS welding process transforms the initial millimeter-sized pancake-shaped grains in the parent material to fine 1 to 5 µm dynamically recrystallized grains; also, the FS welding process redissolves the strengthening precipitates in the weld-nugget region. In the heat-affected zone (HAZ), the initial grain size is retained, while the size of the strengthening precipitates and of the precipitatefree zone (PFZ) is coarsened by a factor of 5. Tensile specimens tested transverse to the weld show that there is a 25 to 30 pct reduction in the strength level, a 60 pct reduction in the elongation in the as-FSW condition, and that the fracture path is in the HAZ. The postweld heat treatment of 121 °C for 24 hours did not result in an improvement either in the strength or the ductility of the welded material. Comparison of fatigue-crack growth rates (FCGRs) between the parent T7451 material and the as-FSW + T6 condition, at a stress ratio of R = 0.33, shows that the FCG resistance of the weldnugget region is decreased, while the FCG resistance of the HAZ is increased. Differences in FCGRs, however, are substantially reduced at a stress ratio of R = 0.70. Analysis of residual stresses, fatigue-crack closure, and fatigue fracture surfaces suggests that decrease in fatigue crack growth resistance in the weld-nugget region is due to an intergranular failure mechanism; in the HAZ region, residual stresses are more dominant than the microstructure improving the fatigue crack growth resistance.
460 citations
Book•
07 Aug 2013TL;DR: In this article, the flow of metal during friction stir welding is investigated using a faying surface tracer and a nib frozen in place during welding, showing that material is transported by two processes: a wiping of material from the advancing front side of the nib onto a zone of material that rotates and advances with the nib.
Abstract: Friction Stir Welding is a relatively new technique for welding that uses a cylindrical pin or nib inserted along the weld seam. The nib (usually threaded) and the shoulder in which it is mounted are rapidly rotated and advanced along the seam. Extreme deformation takes place leaving a fine equiaxed structure in the weld region., The flow of metal during Friction Stir Welding is investigated using a faying surface tracer and a nib frozen in place during welding. It is shown that material is transported by two processes. The first is a wiping of material from the advancing front side of the nib onto a zone of material that rotates and advances with the nib. The material undergoes a helical motion within the rotational zone that both rotates and advances and descends in the wash of the threads on the nib and rises on the outer part of the rotational zone. After one or more rotations, this material is sloughed off in its wake of the nib, primarily on the advancing side. The second process is an entrainment of material from the front retreating side of the nib that fills in between the sloughed off pieces from the advancing side.
396 citations
TL;DR: In this article, the effects of weld residual stress and heat affected zone on the fatigue propagation of cracks parallel and orthogonal to the weld direction in friction stir welded (FSW) 2024-T351 joints were investigated.
385 citations