Investigation on Intermetallic Compounds Formation and Effect of Reinforcing Particles during Friction Stir Vibration Brazing

Friction stir welding of dissimilar formed Mg alloys(AZ31/AZ91) was successfully carried out at the limited welding conditions. In a sound joint, SZ was mainly consisted of AZ31 Mg alloy which was located the retreating side. Dynamic recrystallization and grain growth occurred and β intermetallic compounds of AZ 91 Mg alloy was not observed in SZ. BM had a higher hardness than that of the weld zone. The fracture location was not weld zone but BM of the AZ91 Mg alloy in tensile test.

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Interfacial Reaction during Dissimilar Friction Stir Lap Welding of Aluminum Alloy to Stainless Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.794-796.389 ◽

2014 ◽

Vol 794-796 ◽

pp. 389-394

Author(s):

Tomo Ogura ◽

Taichi Nishida ◽

Makoto Takahashi ◽

Hidehito Nishida ◽

Mitsuo Fujimoto ◽

...

Keyword(s):

Stainless Steel ◽

Aluminum Alloy ◽

Intermetallic Compounds ◽

Lap Joint ◽

Friction Stir Lap Welding ◽

Friction Stir ◽

Transmission Electron ◽

Lap Welding ◽

Mixed Layers ◽

Joining Process

A friction stir welded A3003 aluminum alloy /SUS304 stainless steel dissimilar lap joint was successfully produced. A sound joint that fractured at the base metal was obtained in the center region of the joint through the reaction layer of aluminum-rich intermetallic compounds with nanoorder thickness. The microstructural changes at the interface of the joint was examined by studying the hole left by the extracted welding tool produced at the end of the friction stir welding (FSW) bead using transmission electron microscopy (TEM). Mixed layers consisted of ultra-fined intermetallic compounds and stainless steel were observed. The stirred aluminum alloy flows onto the mixed layer after the tool transit and the joining was achieved. Based on the TEM observations, the joining process of the lap joint was also discussed.

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Formation Investigation of Intermetallic Compounds of Thick Plate Al/Mg Alloys Joint by Friction Stir Welding

Materials ◽

10.3390/ma12172661 ◽

2019 ◽

Vol 12 (17) ◽

pp. 2661 ◽

Cited By ~ 5

Author(s):

Yang Xu ◽

Liming Ke ◽

Yuqing Mao ◽

Qiang Liu ◽

Jilin Xie ◽

...

Keyword(s):

Diffusion Coefficient ◽

Friction Stir Welding ◽

Intermetallic Compounds ◽

Thick Plate ◽

Mg Alloys ◽

Diffusion Reaction ◽

Formation Mechanisms ◽

Phase Identification ◽

Al Alloy ◽

Friction Stir

5A06 Aluminum (Al) alloy and AZ31B magnesium (Mg) alloy with 20 mm thickness were successfully butt joined by friction stir welding. In order to control the composition of Al and Mg alloys along thickness direction, an inclined butt joint was designed in this study. The microstructure and phase identification at the interface of Al/Mg joints were examined using scanning electron microscopy with an energy-dispersive spectroscopy and Micro X-ray diffraction. The results indicated that there were two different formation mechanisms of intermetallic compounds at the interface of thick plate Al/Mg joint. The first was constitutional liquation, and eutectic structure consisting of Al12Mg17 and Mg solid solution existed at the top and upper-middle of the Mg side interface. The second was diffusion reaction, and the two sub-layers of Al12Mg17 and Al3Mg2 formed at the lower middle and bottom of the Mg side interface. In addition, the diffusion thickness values of Al12Mg17 and Al3Mg2 layers decreased gradually from the lower middle to bottom of the Mg side interface. As the position changes from the middle to the bottom near the Mg side interface, the diffusion coefficient of Al3Mg2 phase rapidly decreases from 3.14 × 10−12 m2/s to 6.9 × 10−13 m2/s and the diffusion coefficient of Al12Mg17 phase decreases from 6.8 × 10−13 m2/s to 1.5 × 10−13 m2/s.

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