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.

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.

Localized Corrosion Resistance of Dissimilar Aluminum Alloys Joined by Friction Stir Welding (FSW)

2016 ◽  
Vol 710 ◽  
pp. 41-46 ◽  
Author(s):  
Aline F.S. Bugarin ◽  
Fernanda Martins Queiroz ◽  
Maysa Terada ◽  
Hercílio G. De Melo ◽  
Isolda Costa
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Aluminum Alloys ◽  
Weight Ratio ◽  
Base Material ◽  
High Strength ◽  
Localized Corrosion ◽  
Friction Stir ◽  
Dissimilar Aluminum Alloys

2XXX and 7XXX high strength aluminum alloys are the most used materials for structural parts of aircrafts due to their high strength/weight ratio. Their joining procedure is an engineering challenge since they present low weldability. Friction Stir Welding (FSW) is a joining technology developed in the early 90 ́s. It is a solid-state welding process, without the use of fillers or gas shield, that eliminates conventional welding defects and has been considered of great interest for application in the aircraft industry. FSW of aluminum alloys results in four regions of different microstructures, specifically: the base material (BM), the heat affected zone (HAZ), the thermo-mechanically affected zone (TMAZ), and the nugget zone (NZ). The complex microstructure of the weld region leads to higher susceptibility to localized corrosion as compared to the BM even when similar alloys are joined. The welding of dissimilar alloys in its turn results in even more complex microstructures as materials with intrinsically different composition, microstructures and electrochemical properties are put in close contact. Despite the great interest in FSW, up to now, only few corrosion studies have been carried out for characterization of the corrosion resistance of dissimilar Al alloys welded by FSW. The aim of this study is to investigate the corrosion behavior of aluminum alloy 2024-T3 (AA2024-T3) welded to aluminum alloy 7475-T761 (AA7475-T761) by FSW. The evaluation was performed in 0.01 mol.L-1 by means of open circuit potential measurements, polarization techniques and surface observation after corrosion tests.

scholarly journals Investigation on corrosion behavior of cryogenically treated friction stir welded AA5083

Mechanika ◽  
2020 ◽  
Vol 26 (5) ◽  
pp. 442-449
Author(s):  
Vasudevan NEELAMEGAM ◽  
Bhaskar GOVINDASAMY BHAVANI ◽  
Mohandass MUTHUKRISHNAN ◽  
Srinivasa Rao TADIVAKA
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Ph Value ◽  
Cryogenic Treatment ◽  
Base Material ◽  
Fusion Welding ◽  
Friction Stir ◽  
State Process ◽  
Welding Processes

The aluminum alloy 5083 is widely used as a structural material in marine applications due to very good corrosion resistance and low temperature mechanical properties. Friction stir welding, being a solid state process, offers several benefits over the traditional fusion welding processes. In this study, 10 mm thick AA5083–H321 plates were successfully friction stir welded and the welds were investigated for corrosion behavior using salt fog corrosion tests. The friction stir welds exhibited more corrosion rate compared to that of the base material. However, the corrosion rate was observed to decrease with increase in time of exposure. The cryogenic treatment was found to improve corrosion resistance of the base material and the welds. Furthermore, the corrosion rate increases with decrease in pH value of the salt solution. By and large, it is determined that the cryogenic treatment advantageously effects the corrosion behavior

scholarly journals Mechanical and Microstructural Characterization of Friction Stir Welded SiC and B4C Reinforced Aluminium Alloy AA6061 Metal Matrix Composites

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3110
Author(s):  
Kaveripakkam Suban Ashraff Ali ◽  
Vinayagam Mohanavel ◽  
Subbiah Arungalai Vendan ◽  
Manickam Ravichandran ◽  
Anshul Yadav ◽  
...  
Keyword(s):  
Wear Rate ◽  
Aluminium Alloy ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Weld Zone ◽  
Base Material ◽  
Matrix Composites ◽  
Wear Properties ◽  
Friction Stir ◽  
Behavioural Aspects

This study focuses on the properties and process parameters dictating behavioural aspects of friction stir welded Aluminium Alloy AA6061 metal matrix composites reinforced with varying percentages of SiC and B4C. The joint properties in terms of mechanical strength, microstructural integrity and quality were examined. The weld reveals grain refinement and uniform distribution of reinforced particles in the joint region leading to improved strength compared to other joints of varying base material compositions. The tensile properties of the friction stir welded Al-MMCs improved after reinforcement with SiC and B4C. The maximum ultimate tensile stress was around 172.8 ± 1.9 MPa for composite with 10% SiC and 3% B4C reinforcement. The percentage elongation decreased as the percentage of SiC decreases and B4C increases. The hardness of the Al-MMCs improved considerably by adding reinforcement and subsequent thermal action during the FSW process, indicating an optimal increase as it eliminates brittleness. It was seen that higher SiC content contributes to higher strength, improved wear properties and hardness. The wear rate was as high as 12 ± 0.9 g/s for 10% SiC reinforcement and 30 N load. The wear rate reduced for lower values of load and increased with B4C reinforcement. The microstructural examination at the joints reveals the flow of plasticized metal from advancing to the retreating side. The formation of onion rings in the weld zone was due to the cylindrical FSW rotating tool material impression during the stirring action. Alterations in chemical properties are negligible, thereby retaining the original characteristics of the materials post welding. No major cracks or pores were observed during the non-destructive testing process that established good quality of the weld. The results are indicated improvement in mechanical and microstructural properties of the weld.

scholarly journals Influence of Mx-Trivex, A-Skew, Three Flat Threaded and Concave Shouldered Mx-Triflute Tool Pin Profiles on Tensile Properties and Fractural Behaviour of Aa 6082-T6 Weldments During Friction Stir Welding

2020 ◽  
Vol 9 (4) ◽  
pp. 1376-1384
Keyword(s):  
Friction Stir Welding ◽  
Tensile Test ◽  
Weld Zone ◽  
Base Material ◽  
Traverse Speed ◽  
Friction Stir ◽  
Tool Pin ◽  
Solid State Joining ◽  
Joining Process ◽  
Brass Wire

Friction Stir Welding (FSW) is a topical and propitious solid-state joining process producing economical and strengthened joints of age-hardened and heat-treatable Aluminium Alloy AA 6082-T6. Mechanical and fractural behaviour of weldments were investigated in order to find crack initiation and necking on the weld zone thereby perceiving the complete behaviour of fracture occurred near the weld zone. Weldments are fabricated by employing four tool pin profiles namely MX-TRIVEX, A-SKEW, Three flat threaded and Concave shouldered MX-TRIFLUTE tools at various rotational speeds 1000 rpm, 1200 rpm and 1400 rpm at single traverse speed 25 mm/min. EXCETEX-EX-40 CNC wire cut EDM with 0.25 mm brass wire diameter has been employed to perform the extraction of tensile test specimens from the weldments according to ASTM E8M-04 standard. Tensile test was performed on elctromechanically servo controlled TUE-C-200 (UTM machine) according to ASTM B557-16 standards Maximum Ultimate Tensile Strength (UTS) of 172.33 MPa (55.5% of base material) and 0.2% Yield Stress (YS) of 134.10 MPa (51.5% of base material) were obtained by using A-SKEW at 1400 rpm, 25 mm/min and maximum % Elongation (%El) of 11.33 (113.3% of base material) was obtained at MX-TRIVEX at 1000 rpm, 25 mm/min. Minimum UTS of 131.16 MPa (42.30% of base material) and 0.2% YS of 105.207 MPa (40.46% of base material )were obtained by using Concave shouldered MX-TRIFLUTE at 1400 rpm, 25 mm/min. Minimum % El of 5.42 ( 54.2% of base material) was obtained by using A-SKEW at 1000 rpm, 25 mm/min.

scholarly journals Microstructure and Corrosion Behavior of Friction Stir-Welded 6061 Al/AZ31 Mg Joints with a Zr Interlayer

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1115 ◽  
Author(s):  
Yang Zheng ◽  
Xiaomeng Pan ◽  
Yinglei Ma ◽  
Shuming Liu ◽  
Libin Zang ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Galvanic Corrosion ◽  
Stir Zone ◽  
Thermal Barrier ◽  
Al Alloy ◽  
X Ray ◽  
Friction Stir ◽  
Base Materials ◽  
Dissimilar Alloys ◽  
Scanning Electron

Friction stir welding (FSW) with a Zr interlayer was employed to join dissimilar alloys of 6061 Al and AZ31 Mg. The microstructures of Al/Mg and Al/Zr/Mg joints were investigated by optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive X-ray spectrometer (EDS). The results showed that the central part of the Zr interlayer was smashed and intermixed with the base materials in the stir zone, whereas the undamaged part remained stable at the Al/Mg interface. The formation of Al–Mg intermetallic compounds (IMCs) was suppressed by the Zr interlayer due to its synergetic effects of chemical modification and thermal barrier. The electrochemical measurements revealed a differentiated corrosion behavior for each joint, where the corrosion rate of representative regions increased in the order of Al alloy < Mg alloy < heat-affected zone < stir zone. The immersion tests indicated an enhancement in corrosion resistance for the Al/Zr/Mg joint compared with the Al/Mg joint, which is owing to the mitigated galvanic corrosion between the base materials by the Zr interlayer.

scholarly journals Microstructure Characteristics and Its Effect on the Fracture in the Triple Junction Region of Friction Stir Welded Mg Alloys Subjected to Tension

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3672
Author(s):  
Guodong Liu ◽  
Qunying Yang ◽  
Yongshan Cheng
Keyword(s):  
Triple Junction ◽  
Weld Zone ◽  
Base Material ◽  
Junction Region ◽  
Friction Stir ◽  
Microstructure Characteristics ◽  
Transverse Tension ◽  
Twin Band ◽  
Zone Edge ◽  
Electron Back Scattered Diffraction

Because of the tensile strength decreasing of the friction stir welded wrought magnesium (Mg) alloy compared to the base material, the reasons for the failure of weld has been focused on. After the fracture in transverse tension, the crack went through the welded joint from the center of the weld to the transition zone between the thermal-mechanical affected zone and weld zone. In the present study, the microstructure characteristics and its effect on the facture in the triple junction region is investigated. Based on the metallography and the electron back-scattered diffraction (EBSD) technology, it was observed that a twin band extended from the triple junction region to the middle of weld. The profuse twinning in the twin band was considered to play an important role on the crack propagation from the stir zone edge to the crown zone.

Study of Friction Stir Welding Technics and Weld Performance of Dissimilar 6063-3A21 Aluminum Alloys

2011 ◽  
Vol 299-300 ◽  
pp. 1095-1098 ◽  
Author(s):  
Lei Wang ◽  
Jian Jun Zhu ◽  
Wei Zhang ◽  
Xing Mei Feng ◽  
Zhan Ying Feng
Keyword(s):  
Tensile Strength ◽  
Aluminum Alloys ◽  
Base Material ◽  
Post Weld Heat Treatment ◽  
Weld Strength ◽  
Welding Parameters ◽  
Friction Stir ◽  
Dissimilar Aluminum Alloys ◽  
Performance Results ◽  
Better Than

Several rotating rates and welding speeds were chosen to joint 6063/3A21 dissimilar aluminum alloys, tensile strength of the welds were measured to analyze effect of welding parameters on weld performance. Results show that tensile strength of the weld is better than the base material. Weld tensile strength will decrease under a too high or too low welding speed while effect of rotating rate on weld strength is relatively small. The weakest position is at heat affected zone at 3A21 side after T6 post weld heat treatment.

EFFECT OF FRICTION STIR PROCESSING ON CORROSION BEHAVIOR OF CAST AZ91C MAGNESIUM ALLOY

2019 ◽  
Vol 26 (06) ◽  
pp. 1850213 ◽  
Author(s):  
BEHZAD HASSANI ◽  
RUDOLF VALLANT ◽  
FATHALLAH KARIMZADEH ◽  
MOHAMMAD HOSSEIN ENAYATI ◽  
SOHEIL SABOONI ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Friction Stir Processing ◽  
Potentiodynamic Polarization ◽  
Passive Layer ◽  
Friction Stir ◽  
T6 Heat Treatment ◽  
Az91c Magnesium Alloy

The corrosion behavior of as-cast AZ91C magnesium alloy was studied by performing friction stir processing (FSP) and FSP followed by solution annealing and then aging. Phase analysis, microstructural characterization, potentiodynamic polarization test and immersion tests were carried out to relate the corrosion behavior to the samples microstructure. The microstructural observations revealed the breakage and dissolution of coarse dendritic microstructure as well as the coarse secondary [Formula: see text]-Mg[Formula: see text]Al[Formula: see text] phase which resulted in a homogenized and fine grained microstructure (15[Formula: see text][Formula: see text]m). T6 heat treatment resulted in an excessive growth and dispersion of the secondary phases in the microstructure of FSP zone. The potentiodynamic polarization and immersion tests proved a significant effect of both FSP and FSP followed by T6 on increasing the corrosion resistance of the cast AZ91C magnesium alloy. Improve in corrosion resistance after FSP was attributed to grain refinement and elimination of segregations and casting defects which makes more adhesive passive layer. Increase in volume fraction of precipitations after T6 heat treatment is determined to be the main factor which stabilizes the passive layer at different polarization values and is considered to be responsible for increasing the corrosion resistance.

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