Numerical and experimental study on the thermal process, material flow and welding defects during high-speed friction stir welding. (June 2022)

• Record Type: Journal Article
• Authors: Jia, Hepeng; Wu, Kai; Sun, Yu
• Is Part Of: Materials today communications. Volume 31(2022)
• Publication Date: 2022-06
• Subjects: Friction stir welding -- Thermal process -- Material flow -- Contact friction stress -- Defect prediction; Materials science -- Periodicals; 620.11
• DOI: 10.1016/j.mtcomm.2022.103526
• Languages: English
• ISSNs: 2352-4928

Abstract

Abstract: Friction stir welding (FSW) involves complex interactions between thermal, mechanical and geometric effects. The thermal process and material flow in the welding process significantly influence the microstructure evolution and the final mechanical properties of the joint. This paper aims to determine the influence of the thermal process and material flow on welding defects during high-speed FSW of an aluminum alloy. A thermal-fluid coupling model based on computational fluid dynamics is established, and related experiments are designed to verify the difference in the temperature distribution and the characteristics of the material flow. The results show that the calculation results can accurately describe the quasi-steady state heat-flux coupling state during FSW. In high-speed welding, the material produces a considerable strain rate. The contact friction stress of the tool decreases as the temperature of the material increases. The dynamic recrystallization phenomenon is more evident on the advancing side, but there are tiny void defects on the advancing side. Graphical Abstract: ga1 Highlights: Developed a numerical model for high-speed friction stir welding. The effect of plunge depth, pin taper and tilt angle on the results was considered. The predicted temperature results agree with infrared thermal camera. Discussed welding defects based on simulation and experiment.