Behaviour of oxides during friction stir welding of aluminium alloy and their effect on its mechanical properties

Okamura, Hiroshi; Aota, Kinya; Sakamoto, Masaaki; Ezumi, Makoto; Ikeuchi, Kenji

doi:10.1080/09507110209549530

Cited by 38 publications

(24 citation statements)

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“…With further increases in the weld pitch, the zigzag oxide in the weld nugget became more pronounced as it evolved from a discontinuous to a continuous layer with decreasing heat input (i.e., transformation of the process from hot to cold welding conditions). This phenomenon was observed in previous work by Okamura et al (2002) who reported that below a weld pitch of 0.60 mm/rev, the characteristics of the zigzag oxide are not problematic for the performance of the weld. In the present work, root and face bend testing of joints with different pitch values ( Figure 2) exhibited no cracking even up to a 1808 bend.…”

Section: Fsw Process Window Investigation For Butt-weld Configurationsupporting

confidence: 57%

Process operational windows and industrialization scenarios for assembly of large aluminium structures by robotic friction stir welding

Wanjara¹,

Monsarrat²,

Larose³

2015

Can. Aeronaut. Space J.

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Abstract. In this work, friction stir welding (FSW) of 3.18 mm thick AA6061-T6 sheets in the butt-and lap-joint configuration was investigated with the objective of industrializing the process using low-cost serial industrial robots. The influence of weld pitch on the welding defects, microstructure, hardness, and bend performance of butt and lap welds was examined to identify process operational windows for both joint types. In parallel with these trials, a methodology based on kinetostatic analysis was developed to identify and evaluate viable robotized scenarios for FSW. On the basis of the experimental FSW process development results, this methodology was then applied to identify optimized FSW scenarios for the fabrication of large integrated AA6061 structural components with stringer-to-skin and skin-to-skin joints. Candidate workcell layouts are also presented.Résumé. Dans ce travail, le soudage par friction malaxage (mieux connu sous l'acronyme FSW pour Friction Stir Welding) de feuilles d'aluminium 6061-T6 d'une épaisseur de 3.18 mm dans les configurations bout-à-bout et par recouvrement a été étudié dans l'optique d'industrialiser le procédé via l'utilisation de robots sériels industriels à bas coû t. L'influence du pas de soudage (weld pitch) sur les défauts de soudage, la microstructure, la dureté et la performance en flexion a été examinée afin d'établir les fenêtres opératoires du procédé pour les deux types de soudure. En parallèle de ces essais expérimentaux, une méthodologie basée sur l'analyse cinétostatique a été développée afin d'identifier et d'évaluer des scénarios viables d'implantation du soudage par friction malaxage robotisé. Cette méthodologie a par la suite été appliquée en utilisant les résultats des tests expérimentaux de soudage afin d'identifier des scénarios d'implantation optimisés pour l'assemblage de composants structurels intégrés de grande dimension en AA60601 comprenant à la fois des joints lisse sur revêtement et revêtement sur revêtement. Des scénarios d'implantation potentiels ont été identifiés et sont présentés.

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Section: Fsw Process Window Investigation For Butt-weld Configurationsupporting

confidence: 57%

Process operational windows and industrialization scenarios for assembly of large aluminium structures by robotic friction stir welding

Wanjara¹,

Monsarrat²,

Larose³

2015

Can. Aeronaut. Space J.

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“…Previous work on friction stir welding of 5XXX Al alloys showed the presence of Mg rich oxides at the interface [25]. Characterization using FIB and TEM has shown that the MgO could form during friction stir welding [12]. Such oxide formation occurring at the interfaces during the UAM process could significantly affect the mechanical properties of the build.…”

Section: Transmission Electron Microscopymentioning

confidence: 98%

“…It was also hypothesized that these regions are the first to break while tensile testing [11]. Adding to the complexity, a strong correlation between the mechanical properties and non-oxide defects have also been postulated in other solid-state processes, i.e., friction stir welding [12,13]. The nature of bonding in UAM builds have been characterized before using multi scale characterization including TEM [1,10] and dual beam FIB and electron backscatter diffraction [9,14].…”

Section: Introductionmentioning

confidence: 99%

Rationalization of anisotropic mechanical properties of Al-6061 fabricated using ultrasonic additive manufacturing

et al. 2016

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“…Some fracture surface appeared as wave form, as shown in figure 7, which is identical with the fracture which tensile specimen bearing zigzag line [6]. Zigzag line or lazy S is recently hypothesized to be due to entrapped oxide particles seeping from the specimen surface during welding [7][8]. Okamura et al Due to special keyhole mode and vertical-up process, VPPA welding can facilitate the outflow of the hydrogen generated in the melt.…”

Section: Methodsmentioning

confidence: 57%

Study on defect in the intersection of VPPA and FSW

Chen

Yang

et al. 2011

QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY

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In order to investigate the defects in the intersection of variable polarity plasma arc (VPPA) welding seam with the friction stir welding seam. Different kinds of specimens with crossing and overlapping welding seams were prepared. Defects in the overlapping and crossing welding seam were detected. The mechanism of defects was further explored. At last, the schematic of welding porosity forming were given.

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Behaviour of oxides during friction stir welding of aluminium alloy and their effect on its mechanical properties

Cited by 38 publications

References 1 publication

Process operational windows and industrialization scenarios for assembly of large aluminium structures by robotic friction stir welding

Process operational windows and industrialization scenarios for assembly of large aluminium structures by robotic friction stir welding

Rationalization of anisotropic mechanical properties of Al-6061 fabricated using ultrasonic additive manufacturing

Study on defect in the intersection of VPPA and FSW

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