Process and joint quality of ultrasonic vibration enhanced friction stir lap welding

ABSTRACT

In order to improve the process effectiveness and joint quality, ultrasonic vibrations were integrated with friction stir lap welding. Effect of ultrasonic exertion on the process and joint quality of AA 6061-T6 were investigated. Upon ultrasonic exertion, joints owned larger effective lap width, shorter hooks and improved strength. Weld fracture mode changed from a ductile–brittle mixed mode to a more ductile mode while the fracture path shifted from lap interface to beyond the stir zone. Material flow and interface defects were characterised using lap welded dissimilar aluminium alloy joints. Ultrasonic vibration improved the material flow and reduced the interfacial defects. Variations in failure load of joints were found in accordance with the variations in material flow and interfacial defects.

KEYWORDS:

• Ultrasonic vibration
• friction stir lap welding
• aluminium alloy
• mechanical properties
• material flow

Acknowledgement

GKP acknowledges the Postdoc research fellowship of Shandong University.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors acknowledge the financial support from the National Natural Science Foundation of China [grant no. 51475272].