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.

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.

Recrystallization of AZ31 Alloy

2014 ◽  
Vol 783-786 ◽  
pp. 497-502
Author(s):  
Bensu Tunca ◽  
Emin Erkan Aşik ◽  
G. Ipek Nakaş ◽  
Şakir Bor
Keyword(s):  
Magnesium Alloys ◽  
Volume Fraction ◽  
Az31 Alloy ◽  
Grain Structure ◽  
Recrystallization Behavior ◽  
Complex Deformation ◽  
Different Temperatures ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Deformation Modes

Magnesium alloys are extensively used in electronics, automotive and aerospace industries due to their low densities and high specific strengths. However, limited deformability of magnesium alloys at room temperature restricts the applications. Grain refinement and texture weakening as a result of recrystallization can be used to enhance the deformability of these alloys. In this study, recrystallization behavior of cold rolled and swaged AZ31 alloy is investigated at different temperatures in the range of 200-300°C. Effects of unidirectional and complex deformation modes on recrystallization behavior and microstructure development are studied. Microstructural analyses consisted of the examination of the grain structure and twinned regions by using optical and scanning electron microscopes. The volume fraction of recrystallized grains is determined by image analysis and supported by the hardness measurements.

Al2O3-fortifed AA6061-T6 joint produced via friction stir welding: The effects of traveling speed on microstructure, mechanical, and wear properties

2015 ◽  
Vol 231 (6) ◽  
pp. 534-543
Author(s):  
Mohsen Farahmand Nikoo ◽  
Nader Parvin ◽  
Mohsen Bahrami
Keyword(s):  
Friction Stir Welding ◽  
Close Agreement ◽  
The Other ◽  
Nano Particles ◽  
Wear Properties ◽  
Friction Stir ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron ◽  
Traveling Speed

In this study, 6 mm thick AA6061-T6 alloy was friction stir-welded at different traveling speeds while Al2O3 nano-particles were incorporated between adjoining plates. All joints were investigated macro- and micro-structurally. In addition, distribution pattern of Al2O3 nano-particles in the stir zone was observed via scanning electron microscopes. Although the specimen friction stir-welded at 40 mm/min exhibited the most homogeneous particles distribution, friction stir welding at 1600 rpm and 45 mm/min yielded highest tensile strength. Fractographs achieved from tensile test specimens were in close agreement with corresponding percent elongations. Surprisingly, the foregoing specimen exhibited inferior hardness to the as-received AA6061-T6 alloy. Accordingly, it was concluded that dissolution of strengthening precipitates dominated the effect of hard reinforcement particles on enhancement of hardness value. As a result of Al2O3 nano-particles introduction, on the other hand, wear resistance improved tremendously.

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.

Grain Structure Formation Ahead of Tool during Friction Stir Welding of AZ31 Magnesium Alloy

2010 ◽  
Vol 160 ◽  
pp. 313-318 ◽  
Author(s):  
Uceu Suhuddin ◽  
Sergey Mironov ◽  
H. Takahashi ◽  
Yutaka S. Sato ◽  
Hiroyuki Kokawa ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Magnesium Alloy ◽  
Structure Formation ◽  
Material Flow ◽  
Boundary Migration ◽  
Deformation Mode ◽  
Grain Structure ◽  
Az31 Magnesium Alloy ◽  
Structure Evolution ◽  
Friction Stir

The “stop-action” technique was employed to study grain structure evolution during friction-stir welding of AZ31 magnesium alloy. The grain structure formation was found to be mainly governed by the combination of the continuous and discontinuous recrystallization but also involved geometric effect of strain and local grain boundary migration. Orientation measurements showed that the deformation mode was very close to the simple shear associated with the rotating pin and material flow arose mainly from basal slip.

Sign in / Sign up

Export Citation Format

Share Document