Flow visualization and residual microstructures associated with the friction-stir welding of 2024 aluminum to 6061 aluminum

Liu, Ying; Murr, L. E.; McClure, Joshua P.

doi:10.1016/s0921-5093(99)00204-x

Cited by 290 publications

(148 citation statements)

References 8 publications

Supporting

Mentioning

137

Contrasting

Unclassified

Order By: Relevance

“…This would explain why the actively cooled plate recovers its hardness more quickly and more completely than the conventionally processed plate. Similar softening phenomena have been reported in the literature for pre cipitation hardened aluminum alloys [8,[12][13][14].…”

supporting

confidence: 87%

The mechanical and thick section bending behavior of friction stir processed aluminum plate

et al. 2007

View full text Add to dashboard Cite

Friction stir processing (FSP) 2519-T87 aluminum plate results in enhanced ductility, 25% strain at fracture. However, the yield strength in the FSP zone drops to 175 MPa from �400 MPa. Actively cooling the plate during FSP increases the yield strength to 185 MPa and decreases ductility to 20% strain at fracture. Thick bending of a plate of the alloy was demonstrated after the surface was subjected to FSP.Keywords: Friction stir processing; Severe plastic deformation; Aluminum alloy; Mechanical properties testing; Plate bending Friction stir processing (FSP) is a variation of fric tion stir welding (FSW), a solid-state thermomechanical joining process invented at The Welding Institute in the UK [1][2][3][4]. Since its inception FSW has shown great promise in joining many high strength aluminum alloys that have in the past proven difficult to join using more conventional techniques such as arc welding [5]. Presum ably, all materials that can be friction stir welded could be subjected to FSP due to the similarities between the two processes. In fact, the only major difference between FSW and FSP is the presence of a joint within the material(s) during FSW operations.Additionally, FSP shows promise as a forming aid if used prior to certain forging operations. For example, the bending of thick sections (>2.5 cm) of material at room temperature has proven challenging. As this study will show, by FSP the tensile strained surface of a plate, large amounts of deformation become possible. Overall, both FSP and FSW are relatively new and novel tech niques that will most likely see increased use in a variety of manufacturing environments over the next few decades.The material tested in this investigation is 2519-T87 aluminum plate. 2519 aluminum is an exceptionally strong wrought aluminum-copper alloy with a yield strength and ultimate tensile strength of over 420 and 470 MPa respectively, making it stronger than many * Corresponding author. E-mail: dmhulbert@ucdavis.edu structural steels [4]. Additionally, 2519-T87 has substan tial ductility of over 10% at room temperature [6]. Applications for this alloy range from ballistic armor plating to fuselage components for commercial aircraft. Unfortunately, due to the dispersion strengthening effect of the copper precipitates, the alloy exhibits poor welda bility, making it difficult to join.FSP can expand the horizons of shaping 2519 and other alloys by greatly enhancing formability. In gen eral, it is believed that microstructural defects (inclu sions, pores, cracks, etc.) are broken apart and grains are recrystallized and refined to an equiaxed morpho logy. The microstructure then becomes much more dam age tolerant and susceptible to forming operations at lower temperature [7,8]. Once such forming operation is the thick section bending of large plates (>2 cm thick) at room temperature. This capability carries with it many obvious advantages, including the ability to man ufacture shapes that were previously impossible to make. Additionally, the savings of resources, including...

show abstract

supporting

confidence: 87%

The mechanical and thick section bending behavior of friction stir processed aluminum plate

et al. 2007

View full text Add to dashboard Cite

show abstract

“…Many studies [8][9][10][11] have suggested that fine equiaxed grains at the weld center of the SZ are nucleated through dynamic recrystallization during the stir process of the material. After the grain nucleation, there is a possibility that the dynamically recrystallized grains will experience the grain growth as the stirring operation continues.…”

Section: Discussionmentioning

confidence: 99%

Effect of Microstructural Feature on the Deterioration of Tensile Properties and Vibration Fracture Resistance of FSW 5052-H34 Alloy

2004

View full text Add to dashboard Cite

In this paper, 5052H34 Al-Mg plates are joined by Friction Stir Welding (FSW) at various rotation speeds ranging from 2000 to 2700 min À1 to explore the deterioration of tensile and vibration fracture resistance. An average grain size of 16 AE 1 mm could be observed in the stir zone (SZ) at all rotation speeds. The results of tensile and vibration tests which are done transversely in the stir zone verified that the FSW 5052-H34 specimens become significantly different from the base metal, and the deterioration pertains to the microstructural revolution and joining defects.The best condition of FSW specimens for the test of vibration fracture resistance can be acquired when an optimal tool rotation speed (2400 min À1 ) is selected to avoid microstructural defects. The deterioration of the material in this study can also be recognized in the existence of heat affected zone (HAZ). On the other hand, vibration fracture resistance can be significantly improved if the crack initiation and propagation through the stir zone of FSW are controlled. That is correlated with the formation of the fine grains through dynamic recrystallization in the vicinity of stir zone.

show abstract

“…As is clearly seen, three macro-scale zones can be discerned: Top, Central, and Nugget; in addition, the microstructure varies also within these zones from advancing side (AS) to retreating side (RS). The very specific meso-scale structural features were revealed in Top and Nugget zones; according to Li et al, 12) they were interpreted as flow patterns. They were most obvious in Top zone and had a vortex-like shape, twisted from the border between Top and Nugget zones to surface of the sample.…”

Section: Structure In As-fswed (Initial) Statementioning

confidence: 99%

Grain Growth Behaviors in a Friction-Stir-Welded ZK60 Magnesium Alloy

2007

View full text Add to dashboard Cite

Grain growth during annealing of a friction-stir-welded (FSWed) ZK60 magnesium alloy has been investigated. We have found that (1) thermal stability exhibited in different parts of stirred zone (SZ) was very different, (2) grain growth was fairly abnormal, and (3) grain growth was directional and shapes of developed grains resembled flow patterns inherent to FSWed structure. We have shown that all peculiarities of the grain growth behaviors can be explained in terms of heterogeneous distribution of second phase particles resulted from FSW.

show abstract

Flow visualization and residual microstructures associated with the friction-stir welding of 2024 aluminum to 6061 aluminum

Cited by 290 publications

References 8 publications

The mechanical and thick section bending behavior of friction stir processed aluminum plate

The mechanical and thick section bending behavior of friction stir processed aluminum plate

Effect of Microstructural Feature on the Deterioration of Tensile Properties and Vibration Fracture Resistance of FSW 5052-H34 Alloy

Grain Growth Behaviors in a Friction-Stir-Welded ZK60 Magnesium Alloy

Contact Info

Product

Resources

About