Evolution of microstructure and mechanical properties in naturally aged 7050 and 7075 Al friction stir welds

Fuller, Christian B.; Mahoney, Murray W.; Calabrese, Mike; Micona, Leanna

doi:10.1016/j.msea.2009.11.057

Cited by 250 publications

(93 citation statements)

References 29 publications

(64 reference statements)

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“…Similar displacements in the hardness minima as a function of natural aging time were previously reported by Leonard [8] in friction stir welded aluminum alloys 2014A-T651 and 7075-T651, however, the author did not elaborate on the origin of these displacements in the discussion of the results. This same behavior in the hardness profiles can also be observed in graphs presented by Fuller et al [10] in their research on friction stir welded aluminum 7050 and 7075, but again, the authors did not discuss the phenomenon. Also, the review paper by Threadgill et al [2] displays hardness profiles for naturally aged FSW weld in 7075-T6 alloy in which the positions of the minima clearly change with aging time, but the phenomenon is not addressed in the article.…”

Section: Resultssupporting

confidence: 71%

“…Even though it has been already found that high-quality, sound welds with good mechanical properties may be produced between non-weldable aluminum alloys of the 7000 series [6,7], the phenomena occurring spontaneously after welding (natural aging) in these alloys need further explanation. Some papers discussed this issue [8][9][10][11][12], however, the differences in the course of natural aging in particular alloy weldments call for additional research that provide more evidence for deeper understanding of this apparently simple phenomenon. This study concentrated on the long-term effect of natural aging (up to six years) in friction stir welds of 7136 and 7042 aluminum alloys.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Natural Aging Behavior Of Friction Stir Welded Al-Zn-Mg-Cu Aluminum Alloys

Kalemba

Kopyściański

Hamilton

et al. 2015

Archives of Metallurgy and Materials

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The long term natural aging behavior of friction stir welded aluminum 7136-T76 and 7042 T6 extrusions was investigated. The microstructural characteristics and mechanical properties in the as-welded and six years naturally aged conditions were studied and correlated to a coupled thermal/material flow model of the joining process. Hardness profiles for the 7136 alloy taken along the mid-plane thickness of the workpiece displayed the characteristic W-shape. With natural aging, hardness recovery occurred on both sides of the weld, but the position of the hardness minima, particularly on the advancing side, shifted away from the weld centerline. The hardness profile for the 7042 alloy displayed U-shape in the as-welded condition and W-shape after natural aging. The hardness behavior upon natural aging correlated to the temperature profile developed during welding and the degree to which phase dissolution occurred in the regions adjacent to the stir zone.Keywords: Friction stir welding, Natural aging, Aluminum alloys, Thermal analysis W artykule przedstawiono wyniki badań dotyczące długoterminowego starzenia naturalnego złączy stopów aluminium 7136-T76 i 7042-T6 wykonanych metodą zgrzewania tarciowego z mieszaniem materiału. Złącza w stanie po zgrzewaniu oraz po 6 latach starzenia naturalnego scharakteryzowano pod względem mikrostrukturalnym oraz mechanicznym. Wyniki badań skorelowano z modelem termicznym i modelem płynięcia materiału podczas zgrzewania. Profil twardości złącza stopu 7136 wykazuje charakterystyczny kształt litery "W". Starzenie naturalne powoduje wzrost twardości, przy czym minimum twardości, szczególnie po stronie natarcia, odsuwa się od środka złącza. Profil twardości złącza stopu 7042 przyjmuje kształt litery "U" po zgrzewaniu i kształt litery "W" po starzeniu naturalnym. Takie zachowanie twardości po starzeniu naturalnym jest związane z temperaturą podczas procesu zgrzewania oraz stopniem, w jakim rozpuszczają się fazy w obszarach sąsiadujących ze strefą mieszania.

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Section: Resultssupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Natural Aging Behavior Of Friction Stir Welded Al-Zn-Mg-Cu Aluminum Alloys

Kalemba

Kopyściański

Hamilton

et al. 2015

Archives of Metallurgy and Materials

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“…The 7075 aluminium alloy, in which zinc is the main alloying element, is a precipitation hardened alloy. It is one of the strongest aluminium alloys which is used in many spatial structures and places that require high strength-to-weight ratio [5][6]. Titanium and its alloys have high specific strength and good corrosion resistance and because of these two desirable properties, they have been widely used in the aerospace industry.…”

Section: Introductionmentioning

confidence: 99%

Friction Stir Welding of Dissimilar Joints Between Commercially Pure Titanium Alloy and 7075 Aluminium Alloy

2017

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SummaryIn this study, a joint between commercially pure titanium alloy and 7075 aluminium alloy was butt welded by using friction stir welding at a rotational speed of 1120 rpm and a traverse speed of 50 mmmin -1 . The evaluation of hardness and microstructure was performed by using scanning electron microscopy. The phases in the weld area were identified by applying the X-ray diffraction technique and the Energy Dispersive X-ray Spectroscopy (EDS) analysis was used for the evaluation of intermetallic compounds of the weld area. The weld zone is cone-shaped and consists of aluminium and titanium particles that play an important role in increasing hardness and tensile strength. The weld area has three zones, namely the titanium base metal zone, the aluminium base metal zone, and the titanium-aluminium intermetallic compound mixed zone. It was also observed that the joint area on the aluminium side includes the stirred area, the thermo-mechanically affected zone, and the heat-affected zone, while the titanium joint area contains the stirred zone and the heat-affected zone. The hardness value of the weld area was around 360 HV, which means that in this area, compared to the base metal of titanium and aluminium, hardness has increased by 6% and 20%, respectively. This can be attributed to severe plastic deformation and formation of intermetallic compounds of titanium and aluminium in this area.

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“…Most of the publications are devoted to experimental studies aimed at the optimization of the FSW regimes for particular types of welded joints and to experiments on the microstructure and mechanical properties of welded materials (see, for instance, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]). There is a considerable gap in theoretical and numerical studies on the effect of the microstructure formed in the weld and in the near-weld zones on the operating mechanical characteristics of the FSW joint.…”

Section: Introductionmentioning

confidence: 99%

A mesomechanical analysis of the stress–strain localisation in friction stir welds of polycrystalline aluminium alloys

et al. 2015

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A numerical analysis is presented of the microstructural effects on the deformation and fracture of friction stir welds in aluminium alloys. A dynamic boundary-value problem in a plane strain formulation is solved numerically by the finite-difference method. Experimental polycrystalline microstructures inherent in different weld zones-base material, weld nugget, and thermo-mechanically affected zones-were accounted for explicitly in the calculations. To simulate the mechanical response of individual grains, use was made of an elastic-plastic formulation of the problem accounting for isotropic strain hardening, including the Hall-Petch effect, and of a fracture model allowing for crack initiation and growth in the regions of maximum equivalent plastic strains. Plastic strain and fracture localisation is shown to depend on the strength of welded materials.

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Evolution of microstructure and mechanical properties in naturally aged 7050 and 7075 Al friction stir welds

Cited by 250 publications

References 29 publications

Natural Aging Behavior Of Friction Stir Welded Al-Zn-Mg-Cu Aluminum Alloys

Natural Aging Behavior Of Friction Stir Welded Al-Zn-Mg-Cu Aluminum Alloys

Friction Stir Welding of Dissimilar Joints Between Commercially Pure Titanium Alloy and 7075 Aluminium Alloy

A mesomechanical analysis of the stress–strain localisation in friction stir welds of polycrystalline aluminium alloys

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