Microstructural and Mechanical Behaviour Evaluation of Mg-Al-Zn Alloy Friction Stir Welded Joint

2020 ◽  
Vol 17 (3) ◽  
pp. 8150-8159
Author(s):  
Kulwant Singh ◽  
Gurbhinder Singh ◽  
Harmeet Singh
Keyword(s):  
Heat Treatment ◽  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Mechanical Performance ◽  
Fuel Efficiency ◽  
Research Work ◽  
Grain Structure ◽  
Tensile Fracture ◽  
Friction Stir ◽  
The Impact

The weight reduction concept is most effective to reduce the emissions of greenhouse gases from vehicles, which also improves fuel efficiency. Amongst lightweight materials, magnesium alloys are attractive to the automotive sector as a structural material. Welding feasibility of magnesium alloys acts as an influential role in its usage for lightweight prospects. Friction stir welding (FSW) is an appropriate technique as compared to other welding techniques to join magnesium alloys. Field of friction stir welding is emerging in the current scenario. The friction stir welding technique has been selected to weld AZ91 magnesium alloys in the current research work. The microstructure and mechanical characteristics of the produced FSW butt joints have been investigated. Further, the influence of post welding heat treatment (at 260 °C for 1 h) on these properties has also been examined. Post welding heat treatment (PWHT) resulted in the improvement of the grain structure of weld zones which affected the mechanical performance of the joints. After heat treatment, the tensile strength and elongation of the joint increased by 12.6 % and 31.9 % respectively. It is proven that after PWHT, the microhardness of the stir zone reduced and a comparatively smoothened microhardness profile of the FSW joint obtained. No considerable variation in the location of the tensile fracture was witnessed after PWHT. The results show that the impact toughness of the weld joints further decreases after post welding heat treatment.

Processing, Superplastic Properties and Friction Stir Welding of Fine-Grained AZ31, AZ91, AE42 and QE22 Magnesium Alloys

2016 ◽  
Vol 838-839 ◽  
pp. 220-224 ◽  
Author(s):  
Talant Ryspaev ◽  
M. Janecek ◽  
Robert Kral ◽  
Volker Wesling ◽  
Lothar Wagner
Keyword(s):  
Friction Stir Welding ◽  
Grain Refinement ◽  
Magnesium Alloys ◽  
Mechanical Treatment ◽  
Base Material ◽  
Rate Sensitivity ◽  
Grain Structure ◽  
Friction Stir ◽  
Thermo Mechanical Treatment ◽  
Superplastic Properties

The grain refinement after thermo-mechanical treatment (TMT) was investigated in AZ91, AE42, und QE22 magnesium alloys. The optimal over-aging temperature was determined to be 300 °C in the case of AZ91 and AE42 alloys and 350 °C for QE22 alloy. After optimized TMT, the average grain sizes were 13.5 µm (AE42), 11.1 µm (AZ91) and 1.9 µm (QE22). The QE22 alloy exhibited the superior superplastic properties, with maximum elongation to failure 750 % and strain rate sensitivity parameter m=0.73. The Friction Stir Welding showed that the original base material grain structure of the alloys AZ31 and AZ91 replaced by ultrafine grains in the stir zone. The purpose of the present paper is to present the results of the grain refinement in magnesium alloys by thermo mechanical treatment and stir welding.

scholarly journals The Influence of Friction Stir Welding of Dissimilar AZ31 and AZ91 Magnesium Alloys on the Microstructure and Tensile Properties

2019 ◽  
Vol 16 (2) ◽  
pp. 6675-6683
Author(s):  
N. S. Mohamed ◽  
J. Alias
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Size Variation ◽  
Grain Structure ◽  
Hardness Profile ◽  
Cross Sectional ◽  
Friction Stir ◽  
Az91 Magnesium ◽  
High Aluminum

Joining of magnesium alloys was successfully performed by friction stir welding (FSW) technique. This study was aimed in characterizing the microstructure developed after the FSW and its influence on the mechanical properties. The developed microstructure was observed by using optical microscopy, from the cross-sectional side of welded sample. In this study, FSWed of two dissimilar magnesium (Mg) alloy sheets with low aluminum (AZ31) and high aluminum (AZ91) content were successfully conducted at varied welding speed of 60, 80 and 100 mm/min and tools rotational rate of 800, 1000 and 1200 rpm. The microstructure consists of fine and equiaxed recrystallized grain structure especially at the stir zones. The result of the tensile test indicated that the grain size variation of the joint showed an effect on the mechanical properties and fracture location of the joint. An increasing trend of hardness profile revealed more amount of dissolution of aluminum at the stir zone. From the result, FSW can be concluded as effective joining technique for dissimilar magnesium alloys and produced a defect free joint.

Effect of Pre and Post Weld Heat Treatment on the Mechanical Properties of Friction Stir Welded AA6061-T6 Joint

2020 ◽  
Vol 17 (2) ◽  
pp. 7882-7889 ◽  
Author(s):  
J.C. Verduzco Huarez ◽  
R. Garcia Hernandez ◽  
G. M. Dominguez Almaraz ◽  
J.J. Villalón López
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Research Work ◽  
Base Material ◽  
Welding Process ◽  
Post Weld Heat Treatment ◽  
Friction Stir

This research work focuses on the study of the improvement of mechanical properties, specifically the tensile strength of 6061-T6 aluminum alloy on prismatic specimens with 9.5 mm thickness that has been subjected to friction stir welding process and two heat treatments; solubilized and aging before or after the welding process. Three cases studied and evaluated were, welding of the base material without heat treatment (BMW), solubilized heat treatment and partial aging of the base material before welding (HTBW), and heat treatment of solubilized and aging of the base material after welding (HTAW). The obtained results show an increase of about 10% (20 MPa) of tensile strength for the HTBW process, compared to BMW case. In addition, for the case of HTAW, the obtained tensile resistance presents a joint efficiency of 96%, which is close to the tensile strength of the base material (»310 MPa).

The Evaluation of Weldability for AZ31B-H24 and AZ91C-F Mg Alloys in Friction Stir Welding

2006 ◽  
Vol 321-323 ◽  
pp. 1723-1728 ◽  
Author(s):  
Woong Seong Chang ◽  
Heung Ju Kim ◽  
Joong Suk Noh ◽  
Han Sur Bang
Keyword(s):  
Solid Solution ◽  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Grain Structure ◽  
Solid Solution Hardening ◽  
Microstructural Development ◽  
Friction Stir ◽  
Electron Microscopes ◽  
Hot Rolled ◽  
Scanning Electron Microscopes

In the present study, an investigation has been carried out on the friction stir welding (FSW) of two magnesium alloys. Hot-rolled and Die-casting plates of AZ type magnesium alloys were successfully joined by friction stir welding. AZ31B-H24 and AZ91C-F plates with the thickness of 4mm were used, and the microstructural development in stir zone (SZ) was investigated using optical and scanning electron microscopes. Hardness of SZ in AZ31B-H24 alloy has been slightly decreased due to the coarse structure. On the other hand, Hardness of SZ in AZ91C-F alloy has been remarkably increased due to very fine recrystallized grain structure. The result of EPMA showed Al Solid solution hardening by Solid solution of β intermetallic compound to α-Mg. While tensile strength of the FSWelded AZ31B-H24 alloy showed about 80% values compare to Base metal, AZ91C-F showed about 68% values due to strongly affected by formation of the intermetallic compounds, β-Al12Mg17.

Texture Development during Friction Stir Welding of Magnesium Alloys

2011 ◽  
Vol 702-703 ◽  
pp. 43-47
Author(s):  
Hiroyuki Kokawa ◽  
Yutaka S. Sato ◽  
Sergey Mironov
Keyword(s):  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Material Flow ◽  
Shear Plane ◽  
Stir Zone ◽  
Tool Geometry ◽  
Friction Stir ◽  
Unique Nature ◽  
Plane Direction ◽  
The Impact

The principal features of material flow during friction stir welding (FSW) were illustrated via textural measurements in magnesium alloys. The straining state in the stir zone was demonstrated to be close to the simple-shear deformation with the shear plane/direction aligned with the local surface of the welding tool. Due to the unique nature of FSW process as well as specific character of the welding tool geometry, texture distribution in the stir zone was shown to be inherently inhomogeneous. The impact of this effect on mechanical properties is briefly considered.

Analisa Sifat Mekanik dan Struktur Mikro pada Proses Friction Stir Welding Alumunium 5052

2016 ◽  
Vol 10 (2) ◽  
pp. 105-118
Author(s):  
Tarmizi Tarmizi ◽  
Boy Prayoga
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Friction Stir Welding ◽  
Solid State ◽  
Welding Process ◽  
Butt Joint ◽  
Grain Structure ◽  
Strength Increase ◽  
Friction Stir ◽  
Tensile Strength Increase

Friction stir welding (FSW) is solid state joining technique or the metal didn’t melt when joining process. This method is used the characteristic of the parent metal has not change. This process is widely used for materials, especially aluminum heat treatment usually must be done first before welding, FSW method invented by The Welding Institute W.Thomas from the welding institute (TWI). Friction stir welding process is used to alumunium 5052 T-0 to form butt joint as much as nine plate. Parameter which varied is pin design form with form triangle, cylinder and cone with screw. The next testing which includes the observation radiography test, tensile test, hardnest test and metallography examination. The results of the study that the variation of the form triangle screw, cylinder screw and cone screw cause hardness value and tensile strength increase and a decrease to triangle screw. Of variation this thesis hardness and tensile strength was highest in cylinder screw as big as 38.27 HV and 120.442 MPa.The microstructure results weld tool 2 (pin cylinder screw) produce finer grain structure than the tool 1 (cone with screw) and the tool 3 (triangle screw).ABSTRAK Friction stir welding  (FSW) adalah proses penyambungan material dengan kondisi solid state atau logam tidak meleleh saat di lakukan penyambungan. Metoda ini digunakan agar karakteristik dari logam induk tidak banyak berubah.  Proses ini banyak digunakan untuk  material khususnya alumunium yang biasanya harus di heat treatment terlebih dahulu sebelum dilakukan pengelasan, metoda FSW ditemukan oleh W.Thomas dari The Welding Institute (TWI). Proses FSW dilakukan pada alumunium seri 5052 T0 dengan bentuk sambungan tumpul sebanyak 9 pelat. Paramter yang divariasikan adalah design bentuk pin dengan bentuk segitiga ulir, silinder ulir dan kerucut ulir. Selanjutnya dilakukan pengujian yang meliputi pengamatan  uji radiografi, uji tarik, uji kekerasan dan pemeriksaan metalografi. Hasil penelitian bahwa dengan variasi bentuk pin segitiga ulir, silinder ulir dan kerucut ulir menyebabkan nilai kekerasan dan kekuatan tarik meningkat serta terjadi penurunan pada pin segitiga ulir. Hasil kekerasan dan kekuatan tarik tertinggi terdapat pada silinder ulir sebesar 38.27 HV dan 120.442 MPa. Struktur mikro hasil lasan  tool 2 (pin silinder ulir) menghasilkan struktur butir yang lebih halus dibandingkan dengan tool 1 (kerucut ulir) dan tool 3 (segitiga ulir).Kata kunci: silinder ulir, segitiga ulir, kerucut ulir 

Influence of post welding heat treatment on the microstructure and mechanical properties of friction stir welding joint of AZ31 Mg alloy

2021 ◽  
pp. 095440892199762
Author(s):  
Kulwant Singh ◽  
Gurbhinder Singh ◽  
Harmeet Singh
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Tensile Failure ◽  
Mg Alloy ◽  
Friction Stir ◽  
Microstructure And Mechanical Properties ◽  
Az31 Mg Alloy

At present, magnesium alloys are extensively used in numerous applications due to their light weight and better characteristics. Welding of magnesium alloys is regarded as one of the most complex phenomena in various industries. The friction stir welding of magnesium alloys has encouraged abundant scientific and industrial interest as it has the potency to form a good quality joint. Post welding heat treatment is an appropriate process to further improve the properties or performance of FSW joints. Therefore, the present work aims to join AZ31 Mg alloy plates by friction stir welding, and microstructural and mechanical properties of the joint have been examined. Furthermore, the consequence of post welding heat treatment on the microstructure and mechanical properties of FSW joint has been evaluated. Tensile strength and elongation of FSW joint were about 145.4 ± 4.9 MPa and 9.5 ± 0.9%, respectively. It was found that post welding heat treatment was beneficial in homogenizing grains and to enhance mechanical properties. Tensile strength and elongation of the joint were improved by 4.74% and 15.78% respectively after PWHT. The highest microhardness of stir zone decreased about 6.84% (73 Hv to 68 Hv) after heat treatment and hardness pattern of weld became relatively smooth. Toughness of PWHT joint was 4.5 ± 0.17 Joules. The mode of tensile failure of as-welded and PWHT joint was ductile.

scholarly journals Microstructural Evolutions of 2N Grade Pure Al and 4N Grade High-Purity Al during Friction Stir Welding

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3606
Author(s):  
Tomoya Nagira ◽  
Xiaochao Liu ◽  
Kohasaku Ushioda ◽  
Hidetoshi Fujii
Keyword(s):  
Friction Stir Welding ◽  
Dynamic Recrystallization ◽  
Grain Refinement ◽  
High Purity ◽  
Cube Texture ◽  
Grain Structure ◽  
Welding Temperature ◽  
Friction Stir ◽  
Continuous Dynamic Recrystallization ◽  
Dislocation Annihilation

The grain refinement mechanisms along the material flow path in pure and high-purity Al were examined, using the marker insert and tool stop action methods, during the rapid cooling friction stir welding using liquid CO2. In pure Al subjected to a low welding temperature of 0.56Tm (Tm: melting point), the resultant microstructure consisted of a mixture of equiaxed and elongated grains, including the subgrains. Discontinuous dynamic recrystallization (DDRX), continuous dynamic recrystallization (CDRX), and geometric dynamic recrystallization are the potential mechanisms of grain refinement. Increasing the welding temperature and Al purity encouraged dynamic recovery, including dislocation annihilation and rearrangement into subgrains, leading to the acceleration of CDRX and inhibition of DDRX. Both C- and B/-type shear textures were developed in microstructures consisting of equiaxed and elongated grains. In addition, DDRX via high-angle boundary bulging resulted in the development of the 45° rotated cube texture. The B/ shear texture was strengthened for the fine microstructure, where equiaxed recrystallized grains were fully developed through CDRX. In these cases, the texture is closely related to grain structure development.

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