Effect of microstructure and precipitate formation on mechanical and corrosion behavior of friction stir processed AA6061 alloy using different cooling media

2021 ◽  
pp. 146442072110057
Author(s):  
Marukurti VNV Satyanarayana ◽  
Adepu Kumar ◽  
Shivraman Thapliyal
Keyword(s):  
Corrosion Resistance ◽  
Friction Stir Processing ◽  
Base Alloy ◽  
Base Material ◽  
Stir Zone ◽  
Grain Structure ◽  
Precipitate Formation ◽  
Friction Stir ◽  
Aa6061 Alloy ◽  
Effect Of Microstructure

The present work studies the effect of microstructure and precipitate formation on mechanical and corrosion characteristics of friction stir processed AA6061 alloy using different cooling technologies (cryogenic and water cooling). The results revealed that recrystallized fine grains formed in all friction stir processing samples (grain size within a range of 2–6 µm) as a result of dynamic recovery and recrystallization, while samples processed in cooling-assisted friction stir processing resulted in better grain refinement in the stir zone than in air-cooled friction stir processing. Three kinds of precipitates (Fe-based needle-shaped precipitates, Si-based round-shaped precipitates, and chain of small round-shaped Si-based precipitates) were identified in base material and friction stir processing samples. Compared to air-cooled friction stir processing, in cooling-assisted friction stir processing, the hardness and tensile strength increased but remained lower than for the base alloy due to the presence of high density Fe-based needle-shaped precipitates. The ductility after friction stir processing greatly improved due to thermal softening and dissolution of precipitates. The corrosion results demonstrated that the corrosion resistance greatly enhanced after friction stir processing due to uniform distribution of grain structure and discontinuous chain of small round-shaped Si-based precipitates in stir zone. Moreover, cooling-assisted friction stir processing resulted in improved corrosion resistance compared to air-cooled friction stir processing due to the formation of fine precipitates.

Microstructures and Properties of Biological Mg-Zn-Y-Nd Alloy by Friction Stir Processing

2013 ◽  
Vol 745-746 ◽  
pp. 33-38 ◽  
Author(s):  
Shi Jie Zhu ◽  
Li Guo Wang ◽  
Jin Jin ◽  
Jing Wang ◽  
Yu Feng Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Processing ◽  
Cast Alloy ◽  
Corrosion Current ◽  
Stir Zone ◽  
Grain Structure ◽  
Second Phase ◽  
Uniform Corrosion ◽  
Corrosion Properties ◽  
Friction Stir

In order to improve the mechanical properties and processing performance of the Mg alloys, and to prevent magnesium alloy from non-uniform corrosion and too fast degradation in the degradation process, the biological medical Mg-Zn-Y-Nd alloy was modified by the friction stir processing (FSP) technique in this paper. The microstructural evolution and phase constitute of the stir zone of Mg-Zn-Y-Nd alloy were investigated, the microhardness and the corrosion properties of the alloy after FSP process was studied. The results showed that the FSP parameters had significant influence on the stir zone and thermo-mechanically affected zone. The stir zone experienced severe plastic deformation and complete dynamic recrystallization after FSP. The stir zone consists of fine equiaxed recystallized grains, and thermo-mechanically affected zone (TMAZ) has deformed grain structure. The second phase distributed along grain boundaries in as-cast state was broken during the FSP and transformed into fine, uniform and dispersed particles in the grains. After FSP, the size of grains was reduced from 50μm (as-cast alloy) to 1-2μm. However, the second phase constitution didnt change. The alloy obtained good comprehensive mechanical properties after FSP. The microhardness of alloy after FSP increased from 39HV (as-cast alloy) to 64HV(FSPed alloy). The results of electrochemical tests in simulated body fluid showed that the corrosion potential of FSP alloy increased and corrosion current density decreased, which confirmed the uniform corrosion of FSPed alloy.

scholarly journals Application of Imaging Techniques to Determine the Post-Yield Behaviour of the Heterogeneous Microstructure of Friction Stir Welds

2021 ◽  
Author(s):  
S. Ramachandran ◽  
A. K. Lakshminarayanan ◽  
P. A. S. Reed ◽  
J. M. Dulieu-Barton
Keyword(s):  
Tool Wear ◽  
Mechanical Behaviour ◽  
Base Material ◽  
Grain Morphology ◽  
Stir Zone ◽  
Image Correlation ◽  
Grain Structure ◽  
Weld Nugget ◽  
Heterogeneous Microstructure ◽  
Friction Stir

Abstract Background Friction Stir Welding (FSW) causes intense plastic deformation and consequent thermomechanical interactions resulting in a localised heterogeneous microstructure. To understand the weld mechanical behaviour, it is necessary to identify each microstructural sub-region in the weld. Objective Determine the relationship between the local microstructure and mechanical behaviour of the different microstructural regions in a FSW. Methods Scanning electron microscopy (SEM) identified the microstructural sub-regions of an FSW joint. A novel High-Resolution Digital Image Correlation (HR-DIC) methodology enabled the determination of full-field strain response to provide the mechanical behaviour of the FSW sub-regions. X-ray computed tomography (CT) identified the geometry of the FSW and material composition. Results The grain morphology in the FSW varied in the stir zone with a fine grain structure in the weld nugget and larger grains in the thermomechanical affected zone (TMAZ); the grains were larger in the retreating side (RS) compared to the advancing side (AS). Tungsten deposits were found in the weld nugget and attributed to tool wear. The mechanical properties of the weld subregions showed that the material in the stir zone had a greater yield strength than the base material and the RS of the FSW was much more ductile than the weld nugget and the AS side. The tungsten distributions in the stir zone correlated with the local mechanical behaviour. Conclusions A novel methodology is developed that combines microstructural observations with HR-DIC enabling, for the first time, the FSW sub-region mechanical behaviour, to be related to the local grain morphology and inclusions caused by tool wear.

Simulation and experimental investigation of multi-walled carbon nanotubes/aluminum composite fabrication using friction stir processing

2021 ◽  
pp. 095440892110340
Author(s):  
Mostafa Akbari ◽  
Parviz Asadi
Keyword(s):  
Carbon Nanotubes ◽  
Wear Resistance ◽  
Friction Stir Processing ◽  
Particle Distribution ◽  
Base Alloy ◽  
Stir Zone ◽  
Friction Stir ◽  
Uniform Dispersion ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Multi-walled carbon nanotube/aluminum composites are fabricated on Al–Si cast alloy employing friction stir processing. First, the microstructure of the stir zone, as well as the effect of process parameters on the size of silicon particles, is investigated. Then, the process is numerically simulated using a thermo-mechanically coupled three-dimensional finite element method model. Material flow, as the primary reason for the dispersion of reinforcing particles, is considered in the numerical model, and proper conditions to obtain a uniform dispersion of multi-walled carbon nanotubes are determined. Scanning electron microscope analysis is carried out to consider the particle distribution in the texture of the stir zone. The results show that the particle distribution improves significantly by changing the tool rotation direction between the friction stir processing passes. The hardness test is accomplished on the cross-section of the friction stir processed specimens, and finally, the wear test is performed to compare the wear resistance of the composites with the base alloy. The results show that the wear resistance and hardness of the produced composites are considerably enhanced compared to the base alloy.

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%.

Enhancement of Formability in Magnesium Alloy AZ31B via Friction Stir Processing

2007 ◽  
Vol 539-543 ◽  
pp. 3775-3780 ◽  
Author(s):  
Yutaka S. Sato ◽  
A. Sasaki ◽  
A. Sugimoto ◽  
A. Honda ◽  
Hiroyuki Kokawa
Keyword(s):  
Grain Size ◽  
Friction Stir Processing ◽  
Base Material ◽  
Mg Alloys ◽  
Stir Zone ◽  
Mg Alloy ◽  
Homogeneous Microstructure ◽  
Friction Stir ◽  
Magnesium Alloy Az31b ◽  
Plane Strain Deformation

Mg alloy has a poor formability at room temperature because of lack of the active slip systems, but the grain refinement improves its ductility. Friction stir processing (FSP) can create homogeneous microstructure consisting of fine grains in Mg alloys, thus it would be expected that FSP enhances the formability of Mg alloys. In this study, multi-pass FSP was applied to Mg alloy AZ31B, and then formability of FSPed alloy was evaluated. Multi-pass FSP produced the fine recrystallized grains in Mg alloy. The stir zone exhibited larger fracture limit major strains than the base material under uniaxial tension and plane strain deformation, and these values increased with decreasing grain size. The stir zone having grain size of 2.9 μm showed the fracture limit major strains which are roughly as same as those of an annealed pure Al. The present study suggests that FSP is an effective method to enhance the formability of Mg alloys.

scholarly journals Effect of III-Pass on Microstructure, Micro Hardness and Static Immersion Corrosion Resistance of AA6061-T6/SiCp Surface Composite Fabricated by Friction Stir Processing

2012 ◽  
pp. 152-156
Author(s):  
Devaraju Aruri ◽  
Adepu Kumar ◽  
B Kotiveerachary
Keyword(s):  
Corrosion Resistance ◽  
Friction Stir Processing ◽  
Stir Zone ◽  
Al Alloy ◽  
Micro Hardness ◽  
Friction Stir ◽  
Surface Composite ◽  
Sic Particles ◽  
Immersion Corrosion ◽  
Static Immersion

In this current investigation, SiC particles 20μm in average size were incorporated into the commercially AA6061-T6 to prepare surface composite by using Friction stir processing (FSP). The morphology of the reinforcement inside the Al matrix has been evaluated from scanning electron microscope (SEM) and the corrosion characteristics of the resulted composite were evaluated using static immersion corrosion (SIC) behavior in 3.5% NaCl aqueous solution at various regimes. From the results, it observed that the SiC particles were distributed uniformly inside the stir zone (SZ) in both first and third-pass of FSP. The micro hardness of stir zone with SiC particles of I-pass was higher compared to III-pass and as-received Al alloy. In static immersion corrosion test the FSP AA6061-T6/SiCp exhibited significantly greater corrosion resistance in I-pass than compared to the III-pass and as-received Al alloy.

scholarly journals Improving the Wear Properties of Aluminum 6082 Alloy by Surface Compositing with Zro2 Ceramic Particles Via Friction Stir Processing

2018 ◽  
Vol 15 (1) ◽  
pp. 68-74
Author(s):  
N. Yuvaraj
Keyword(s):  
Friction Stir Processing ◽  
Volume Content ◽  
Surface Engineering ◽  
Base Alloy ◽  
Base Material ◽  
Matrix Composites ◽  
Wear Properties ◽  
Friction Stir ◽  
Surface Composites ◽  
Lower Volume

Aluminum based metal matrix composites are given more attention in fabrication of surface engineering applications due to their excellent mechanical and wear properties. In this study, Friction stir processing (FSP) method was used to fabricate the surface composite with inserting different volume % of ZrO2 reinforcement particles in the Aluminum 6082 alloy. The hardness and triblogical characteristics of fabricated surface composites and base alloy were investigated. The higher volume content of reinforcement surface revealed higher hardness and higher wear resistance compared to the lower volume content reinforcement surface and base material. The wear worn-out of composite surfaces and base alloy were examined through SEM for understanding the wear mechanisms.

FORMALOY

Alloy Digest ◽  
1975 ◽  
Vol 24 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Corrosion Resistance ◽  
Sheet Metal ◽  
High Purity ◽  
Base Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Grain Structure ◽  
Excellent Performance

Abstract FORMALOY is a high-strength, high-purity zinc-base alloy with excellent performance in dies for forming sheet metal. It has a fine, dense grain structure which contributes markedly to its good toughness, excellent machinability and ability to develop a high polish. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on corrosion resistance as well as casting, forming, heat treating, machining, and joining. Filing Code: Zn-17. Producer or source: Federated Metals Corporation, ASARCO Inc..

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