Study on the effect of the welding environment on the dynamic recrystallization phenomenon and residual stresses during the friction stir welding process of aluminum alloy

2021 ◽  
pp. 146442072110251
Author(s):  
Mahmoud Abbasi ◽  
Amin Abdollahzadeh ◽  
Behrouz Bagheri ◽  
Ahmad Ostovari Moghaddam ◽  
Farzaneh Sharifi ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Residual Stresses ◽  
Welding Process ◽  
Friction Stir ◽  
Friction Stir Welding Process ◽  
Underwater Friction Stir Welding ◽  
Processed Sample ◽  
Vibration Welding ◽  
Strength And Ductility

Various methods have been proposed to modify the friction stir welding. Friction stir vibration welding and underwater friction stir welding are two variants of this technique. In friction stir vibration welding, the adjoining workpieces are vibrated normal to the joint line while friction stir welding is carried out, while in underwater friction stir welding the friction stir welding process is performed underwater. The effects of these modified versions of friction stir welding on the microstructure and mechanical characteristics of AA6061-T6 aluminum alloy welded joints are analyzed and compared with the joints fabricated by conventional friction stir welding. The results indicate that grain size decreases from about 57 μm for friction stir welding to around 34 μm for friction stir vibration welding and about 23 μm for underwater friction stir welding. The results also confirm the evolution of Mg2Si precipitates during all processes. Friction stir vibration welding and underwater friction stir welding processes can effectively decrease the size and interparticle distance of precipitates. The strength and ductility of underwater friction stir welding and friction stir vibration welding processed samples are higher than those of the friction stir welding processed sample, and the highest strength and ductility are obtained for underwater friction stir welding processed samples. The underwater friction stir welding and friction stir vibration welding processed samples exhibit about 25% and 10% higher tensile strength compared to the friction stir welding processed sample, respectively. The results also indicate that higher compressive residual stresses are developed as underwater friction stir welding and friction stir vibration welding are applied.

Simulation on Temperature Field of Friction Stir Welding of 2A14 Aluminum Alloy Based on Equivalent Film Method

2016 ◽  
Vol 723 ◽  
pp. 62-67
Author(s):  
Zhi Zhu ◽  
Min Wang ◽  
Hui Jie Zhang ◽  
Xiao Zhang ◽  
Tao Yu ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Temperature Field ◽  
Friction Stir Welding ◽  
Heat Conduction Problem ◽  
Fluid Dynamic ◽  
Welding Process ◽  
Friction Stir ◽  
Friction Stir Welding Process ◽  
Backing Plate ◽  
Film Method

Backing plate has an important influence on the temperature field of workpiece during the friction stir welding process. In order to predict the temperature field of workpiece accurately, a thermal-fluid coupled friction stir welding calculation model including workpiece and backing plate was developed. In the model, an equivalent film method was proposed to simplify the contact heat transfer between workpiece and backing plate to a heat conduction problem. The computational fluid dynamic software FLUENT was ultilized to simulate the friction stir welding process of 2A14 aluminum alloy. As a result, the steady-state temperature field during the friction stir welding process was predicted and analyzed. The welding process test was carried out to verify the simulation results of temperature field. The compared results show that the simulated temperature and the measured values of all measuring points are in good agreement. Using the simulation method proposed in this paper, the calculation accuracy of temperature field during the friction stir welding process could be relatively high and the maximum error is 4.61%. In addition, there is a good corresponding relationship between the temperature distribution and the various regions of weld cross section.

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