Corrosion Resistance Evaluation and Effects of Prior Corrosion and Stress on Fatigue Behavior of Friction Stir Welded AA2024-T3

CORROSION ◽  
10.5006/2447 ◽  
2017 ◽  
Vol 74 (2) ◽  
pp. 169-180 ◽  
Author(s):  
Takao Okada ◽  
Shigeru Machida ◽  
Toshiya Nakamura
Keyword(s):  
Corrosion Resistance ◽  
Fatigue Life ◽  
Fatigue Behavior ◽  
Base Material ◽  
Corrosion Damage ◽  
Al Alloy ◽  
Line Energy ◽  
Friction Stir ◽  
Aspect Ratios ◽  
Corrosion Pits

The corrosion resistance of 2024-T3 (UNS A92024) Al alloy with no clad layer and that of friction stir welded (FSW) joint specimens fabricated from the same material were evaluated. The surfaces of both the alloy base material and FSW joint specimens were ground out before being exposed to a 3.0% sodium chloride solution at 60°C for 24, 48, 72, or 96 h. The corrosion pits on the base material samples were found to be randomly distributed, while those on the FSW joint were formed around the edge and center of the weld line. Energy dispersive x-ray spectrometry indicated constituent particles containing Mg at the grain boundaries in the thermomechanically affected zone and stir zone of the FSW joint; this Mg content aggravated the corrosion damage in those regions. The depth and volume of the corrosion pits in the FSW joint were greater than those in the base material. However, the aspect ratios of the corrosion pits in the base material and FSW were similar. Prior-corroded specimens were fatigue tested to evaluate the effect of corrosion damage. The fatigue life of the base material with corrosion damage was slightly shorter than that of the FSW joint specimens with corrosion damage, and the fatigue life of an uncorroded FSW joint specimen was more than 10 times longer than that of a corroded specimen. Thus, corrosion damage has a severely detrimental effect on fatigue life. Further, fracture surface observation revealed that the fracture origins in the FSW joint specimens tended to be multiple corrosion pits; however, the corrosion pits with the greatest depth or volume did not necessarily become fracture origins in the base material or FSW joints.

Effect of friction stir processing on electrical conductivity and corrosion resistance of AA6063-T6 Al alloy

2008 ◽  
Vol 222 (7) ◽  
pp. 1117-1123 ◽  
Author(s):  
T S Mahmoud
Keyword(s):  
Electrical Conductivity ◽  
Corrosion Resistance ◽  
Friction Stir Processing ◽  
Rotational Speed ◽  
Mechanical Characteristics ◽  
Base Material ◽  
Al Alloy ◽  
Friction Stir ◽  
Electrical Conductivities ◽  
Hcl Solution

The aim of this paper is to study the effect of friction stir processing (FSP) on electrical conductivity and corrosion resistance of AA6063-T6 Al alloy. Also, the microstructural and mechanical characteristics were examined. Different samples were structured by employing a constant feed rate (ν) of 120 mm/min and different rotating speeds (ω) of 250, 315, 400, 500, 630, and 800 r/min. The results showed that FSP significantly refines the microstructure of the AA6063-T6 Al alloy. Increasing the rotational speed increases the grain size in the centres of stirred zones (SZ). The FSP significantly increases the electrical conductivity of the alloy. The highest electrical conductivities were observed at the centres of the SZ for the alloys processed with varying rotational speeds between 315 and 500 r/min. Increasing the rotational speed above this range tends to reduce the electrical conductivity, but it is still higher than the base material. In contrast, the corrosion resistance was found to decrease due to FSP of the AA6063-T6 aluminium alloy. It has been found that, increasing the rotational speed decreases the corrosion resistance of the SZ in 1 M HCl solution.

scholarly journals Influence of Friction Stir Processing on Mechanical Behavior of 2507 SDSS

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 369 ◽  
Author(s):  
Hafiz M. Abubaker ◽  
Necar Merah ◽  
Fadi A. Al-Badour ◽  
Jafar Albinmousa ◽  
Ahmad A. Sorour
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Fatigue Life ◽  
Duplex Stainless Steel ◽  
Friction Stir Processing ◽  
Base Material ◽  
Pressure Vessels ◽  
Friction Stir

Duplex stainless steel (DSS) is used for desalination equipment, pressure vessels, marine applications, offshore applications, and in oil/gas plants where a highly corrosive environment is present. Super duplex stainless steel (SDSS) 2507 has excellent mechanical properties, such as high strength, high toughness, high fatigue life, and high corrosion resistance. Friction stir processing (FSP) is used to refine the grain structure of the processed region such that properties like strength, hardness, fracture toughness, fatigue life, and corrosion resistance are enhanced. In this paper, an optimized friction stir process of 2507 SDSS is carried out to refine the microstructure of the material in order to improve its mechanical properties. Microstructure analysis revealed that grains were refined from a size of around 160 µm in the base material to 2–30 µm in the processed zone. This grain size reduction resulted in improved strength, hardness, and fracture toughness of the material by up to 14%, 11%, and 12%, respectively. However, FSP has reduced the fracture strain by about 30%.

scholarly journals Assessment of the Corrosion Behavior of Friction-Stir-Welded Dissimilar Aluminum Alloys

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 260
Author(s):  
Rami Alfattani ◽  
Mohammed Yunus ◽  
Ahmed F. Mohamed ◽  
Turki Alamro ◽  
Mohamed K. Hassan
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Weld Zone ◽  
Base Material ◽  
Sem Analysis ◽  
Al Alloy ◽  
Suitable Material ◽  
Friction Stir ◽  
Dissimilar Aluminum Alloys ◽  
Weld Area

The fuel consumption of high-density automobiles has increased in recent years. Aluminum (Al) alloy is a suitable material for weight reduction in vehicles with high ductility and low weight. To address environmental problems in aircraft and maritime applications, in particular rust development and corrosion, the current study assesses the corrosion behavior during friction stir welding (FSW) of two dissimilar Al alloys (AA6061 and AA8011) in various corrosive conditions using salt spraying and submersion tests. Two acidic solutions and one alkaline solution are used in these tests, which are performed at room temperature. The two specimens (AA6061 and AA8011) and the weld region are suspended in a salt spraying chamber and a 5 wt.% NaCl solution is continually sprayed using the circulation pump for 60 h, with the specimens being weighed every 15 h to determine the corrosion rates. According to the salt spraying data, the weld zone has a higher corrosion resistance than the core components. For twenty-eight days, individual specimens are submerged in 3.5 wt.% HCl + H2O and H2SO4 + H2O solutions and seawater. The weld area specimens exhibit stronger corrosion resistance than the base material specimens, and weight loss in the saltwater medium is lower when compared to the other test solutions, according to the corrosion analysis. The scanning electron microscope (SEM) analysis demonstrates that the base metal AA8011 is considerably corroded on its surface.

scholarly journals Fatigue Modeling and Numerical Analysis of Re-Filling Probe Hole of Friction Stir Spot Welded Joints in Aluminum Alloys

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2171
Author(s):  
Armin Yousefi ◽  
Ahmad Serjouei ◽  
Reza Hedayati ◽  
Mahdi Bodaghi
Keyword(s):  
Experimental Data ◽  
Tensile Strength ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Behavior ◽  
Element Model ◽  
Plastic Strain Amplitude ◽  
Friction Stir ◽  
Probe Hole ◽  
Good Agreement

In the present study, the fatigue behavior and tensile strength of A6061-T4 aluminum alloy, joined by friction stir spot welding (FSSW), are numerically investigated. The 3D finite element model (FEM) is used to analyze the FSSW joint by means of Abaqus software. The tensile strength is determined for FSSW joints with both a probe hole and a refilled probe hole. In order to calculate the fatigue life of FSSW joints, the hysteresis loop is first determined, and then the plastic strain amplitude is calculated. Finally, by using the Coffin-Manson equation, fatigue life is predicted. The results were verified against available experimental data from other literature, and a good agreement was observed between the FEM results and experimental data. The results showed that the joint’s tensile strength without a probe hole (refilled hole) is higher than the joint with a probe hole. Therefore, re-filling the probe hole is an effective method for structures jointed by FSSW subjected to a static load. The fatigue strength of the joint with a re-filled probe hole was nearly the same as the structure with a probe hole at low applied loads. Additionally, at a high applied load, the fatigue strength of joints with a refilled probe hole was slightly lower than the joint with a probe hole.

scholarly journals Microstructural Evolution and Mechanical Properties of Friction Stir Welded Butt Joints of 5A06 Alloy Ultra-Thin Sheets

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3906 ◽  
Author(s):  
Yang Han ◽  
Xiaoqing Jiang ◽  
Tao Yuan ◽  
Shujun Chen ◽  
Dongxiao Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Grain Boundaries ◽  
Microstructural Evolution ◽  
Welding Speed ◽  
Base Material ◽  
Thin Plates ◽  
Al Alloy ◽  
Minimum Thickness ◽  
Friction Stir

Ultra-thin plates have great potential for applications in aircraft skin, the packaging industry, and packaging of electronic products. Herein, 1 mm-thick 5A06 Al alloy was welded with friction stir welding. The microstructural evolution of the welds was investigated in detail with optical microscopy, scanning electron microscopy, and electron backscatter diffraction. The results showed that the friction stir welds of 1 mm-thick 5A06 Al alloy were well formed without obvious defect and with a minimum thickness reduction of 0.025 mm. Further, the grain size and the proportion of low-angle grain boundaries decreased with decreasing welding speed, because of the increasing degree of dynamic recrystallization. Among all of the welded joints, the welding speed of 100 mm/min yielded the smallest grain size and the highest proportion of high-angle grain boundaries, and thus the best mechanical properties. Specifically, the tensile strength of the joint was greater than that of the base material, while the elongation reached 80.83% of the base material.

Fatigue Behavior of Magnesium AZ31 in Friction Stir Spot Welds

2009 ◽  
Author(s):  
J. B. Jordon ◽  
M. F. Horstemeyer ◽  
H. Badarinarayan ◽  
J. Grantham
Keyword(s):  
Fatigue Life ◽  
Crack Growth ◽  
Fatigue Behavior ◽  
Spot Welds ◽  
Friction Stir ◽  
Lap Shear ◽  
Magnesium Az31 ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Crack Growth Modeling

In this study, the fatigue behavior of AZ31 magnesium friction stir spot welded joints is experimentally investigated. The friction stir spot welds employed here are representative of preliminary welds made in developing the joining process for potential use in automobile manufacturing. Load control cyclic tests were conducted on single weld lap-shear coupons and were fatigued until failure to determine stress-life properties. The fractured coupons were examined under optical and scanning electron microscopes with the intent to determine fatigue crack characteristics. Fractography analysis suggests that long crack growth accounts for a majority of the fatigue life. To predict the fatigue life of the lap-joint coupons, a long crack growth modeling approach, based on a kinked crack stress intensity solution, was employed. The fatigue model predictions compared well to the experimental stress-life results.

scholarly journals Corrosion Resistance and Pitting Behaviour of Low-Carbon High-Mn Steels in Chloride Solution

2016 ◽  
Vol 61 (2) ◽  
pp. 825-832
Author(s):  
A. Grajcar ◽  
B. Grzegorczyk ◽  
A. Kozłowska
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behaviour ◽  
Cold Deformation ◽  
Metallic Matrix ◽  
Corrosion Damage ◽  
Austenitic Steels ◽  
Low Carbon ◽  
Deformation Bands ◽  
Cold Worked ◽  
Corrosion Pits

Abstract Corrosion resistance of the X4MnSiAlNbTi27-4-2 and X6MnSiAlNbTi26-3-3 type austenitic steels, after hot deformation as well as after cold rolling, were evaluated in 3.5% NaCl solution using potentiodynamic polarization tests. A type of nonmetallic inclusions and their pitting corrosion behaviour were investigated. Additionally, the effect of cold deformation on the corrosion resistance of high-Mn steels was studied. The SEM micrographs revealed that corrosion damage formed in both investigated steels is characterized by various shapes and an irregular distribution at the metallic matrix, independently on the steel state (thermomechanically treated or cold worked). Corrosion pits are generated both in grain interiors, grain boundaries and along the deformation bands. Moreover, corrosion damage is stronger in cold deformed steels in comparison to the thermomechanically treated specimens. EDS analysis revealed that corrosion pits preferentially nucleated on MnS and AlN inclusions or complex oxysulphides. The morphology of corrosion damage in 3.5% NaCl supports the data registered in potentiodynamic tests.

scholarly journals On the Fatigue Performance of Friction-Stir Welded Aluminum Alloys

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4246
Author(s):  
Sergey Malopheyev ◽  
Igor Vysotskiy ◽  
Daria Zhemchuzhnikova ◽  
Sergey Mironov ◽  
Rustam Kaibyshev
Keyword(s):  
Residual Stress ◽  
Fatigue Strength ◽  
Aluminum Alloys ◽  
Fatigue Behavior ◽  
Base Material ◽  
Fatigue Performance ◽  
Coarse Grained ◽  
Original Material ◽  
Friction Stir ◽  
Macro Scale

This work was undertaken in an attempt to ascertain the generic characteristics of fatigue behavior of friction-stir welded aluminum alloys. To this end, different alloy grades belonging to both the heat-treatable and non-heat-treatable types in both the cast and wrought conditions were studied. The analysis was based on the premise that the fatigue endurance of sound welds (in which internal flaws and surface quality are not the major issues) is governed by residual stress and microstructure. Considering the relatively low magnitude of the residual stresses but drastic grain refinement attributable to friction-stir welding, the fatigue performance at relatively low cyclic stress was deduced to be dictated by the microstructural factor. Accordingly, the fatigue crack typically nucleated in relatively coarse-grained base material zone; thus, the fatigue strength of the welded joints was comparable to that of the parent metal. At relatively high fatigue stress, the summary (i.e., the cyclic-plus residual-) stress may exceed the material yield strength; thus, the fatigue cracking should result from the preceding macro-scale plastic deformation. Accordingly, the fatigue failure should occur in the softest microstructural region; thus; the fatigue strength of the welded joint may be inferior to that of the original material.

scholarly journals Tensile and Fatigue Analysis Based on Microstructure and Strain Distribution for 7075 Aluminum FSW Joints

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1610
Author(s):  
Guoqin Sun ◽  
Xinhai Wei ◽  
Deguang Shang ◽  
Shujun Chen ◽  
Lianchun Long ◽  
...  
Keyword(s):  
Crack Initiation ◽  
Fatigue Fracture ◽  
Strain Distribution ◽  
Fatigue Behavior ◽  
Base Material ◽  
Nugget Zone ◽  
Friction Stir ◽  
Tension Tests ◽  
Deformation And Fracture ◽  
Stress Ratios

In order to study on tensile and fatigue fracture mechanism of friction stir welded (FSW) joints, the tensile and fatigue behavior of FSW joints are studied based on the microstructure and strain distribution. The large plastic deformation and fracture occurred in the thermo-mechanically affected zone (TMAZ) on retreating side in tension tests. High contents of shear texture and small angle grain boundary reduce the tensile mechanical property of TMAZ material. The fatigue weak area for FSW joints is affected by the loading condition. The strain concentration in the welded nugget zone (WNZ) and base material makes the fatigue fracture liable to happen in these areas for the FSW joints under the stress ratios of 0.1 and −0.3. When the fracture occurred in WNZ, the crack initiation mainly occurred in clusters of hardened particles, while when the fracture happened in base material, the crack initiation mainly occurred near the pit. The crack in WNZ propagated in an intergranular pattern and the crack in the other areas extended in a transgranular mode, leading to a higher crack growth rate of WNZ than of other regions.

Corrosion Behaviour of Ti-48Al-2Nb-2Cr Alloys

2012 ◽  
Vol 323-325 ◽  
pp. 301-307
Author(s):  
B. Pelic ◽  
D. Rafaja ◽  
Patrick J. Masset ◽  
H.J. Seifert ◽  
L. Bortolotto ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Protective Coatings ◽  
Corrosion Behaviour ◽  
Base Material ◽  
High Temperature Corrosion ◽  
Al Alloy ◽  
Environmental Embrittlement ◽  
Structural Applications

γ-TiAl intermetallics are attractive materials for high-temperature structural applications in the aerospace and automobile industries. However, they show environmental embrittlement at elevated temperatures that is mainly related to their low high-temperature corrosion resistance. One way how to improve the high-temperature corrosion resistance is the deposition of protective coatings on the surface of the base material. In this study, samples of a Ti-Al alloy with the chemical composition Ti-48Al-2Cr-2Nb (at.%) were covered by physically vapour deposited (PVD), by metalorganic chemically vapour deposited (MOCVD) and by high-velocity oxy-fuel (HVOF) sprayed coatings. All coatings were based on the Ti-Al alloys and contained different amounts of alloying elements. The corrosion experiments were performed in molten salts containing 75 wt.% Na2SO4and 25 wt.% NaCl at 850°C up to 336 h. Both, PVD and CVD protected coatings reduced the changes in the mass of the samples over the corrosion time. Still, the formation of TiO2could not be avoided, as it was confirmed by glancing-angle X-ray diffraction experiments.

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