Interface strengthening in dissimilar double-sided friction stir spot welding of AZ31/ZK60 magnesium alloys by adjustable probes

2021 ◽  
Vol 85 ◽  
pp. 158-168
Author(s):  
Xiaopei Wang ◽  
Yoshiaki Morisada ◽  
Hidetoshi Fujii
Author(s):  
YongBing Li ◽  
ZeYu Wei ◽  
YaTing Li ◽  
ZhaoZhao Wang ◽  
Xiaobo Zhu

Implementation of lightweight low-ductility materials such as aluminum alloys, magnesium alloys and composite materials has become urgently needed for automotive manufacturers to improve the competitiveness of their products. However, the hybrid use of these materials poses big challenges to joining processes. Self-piercing riveting (SPR) is currently the most popular technique for joining dissimilar materials and has been widely used in joining all-aluminum and multi-material vehicle bodies. However, in riveting magnesium alloys, cracks always occur for its low ductility. In this paper, a hybrid joining process named friction self-piercing riveting (F-SPR), which combines mechanical joining mechanism of SPR with solid-state joining mechanism of friction stir spot welding (FSSW) by making rivet rotating at high speed in riveting process, was proposed aiming at joining the low ductility materials. 1-mm-thick AA6061-T6 and 2-mm-thick AZ31B were used to validate the effectiveness of the F-SPR process. The results showed that the F-SPR process could significantly improve the rivetability of magnesium alloys, and greatly increase the joint strength, comparing with traditional SPR process.


2021 ◽  
pp. 109997
Author(s):  
Banglong Fu ◽  
Junjun Shen ◽  
Uceu F.H.R. Suhuddin ◽  
Ayrton A.C. Pereira ◽  
Emad Maawad ◽  
...  

Author(s):  
Jicheng Gao ◽  
Jiachen Dong ◽  
Sunyi Zhang ◽  
Liang Yu ◽  
Huiming Jin ◽  
...  

In this research, thermoplastic polyimide (TPI) were welding via friction stir spot welding (FSSW) in order to evaluate the feasibility of the technology. The welding tool with a tri-flute pin was used for keeping the welding effectiveness. The effect of the rotation speed and dwell time on the microstructure and shear strength was studied. The results shows that the number of gap defects between the shoulder affect zone and the pin affect zone decreased with the increase of the rotation speed. The boundary of the shoulder affect zone and the pin affect zone was no clear when increasing the dwell time from 10 s to 20 s. Long dwell time could increase the mixing time and reduce the materials viscosity, which made the structure was denser. The maximal shear strength was obtained 85.5% of the base materials. The differential scanning calorimetry (DSC) results indicated that the melting behaviour of different regions was no obvious difference. It indicated that FSSW had a feasible and potential technology to join the high temperature resistant engineering plastics.


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