Fatigue Behaviour of 7N01-T4 Aluminium Alloy Welded by Ultrasonic-Assisted Friction Stir Welding

Zhang, Zhiqiang; He, Changshu; Li, Ying; Wei, Jingxun; Zhai, Menggang; Zhao, Su; Zhao, Xiang

doi:10.3390/ma13204582

Open AccessArticle

Fatigue Behaviour of 7N01-T4 Aluminium Alloy Welded by Ultrasonic-Assisted Friction Stir Welding

by

Zhiqiang Zhang

^1,2,

Changshu He

^1,2,*,

Ying Li

^1,2,

Jingxun Wei

^1,2,

Menggang Zhai

³,

Su Zhao

³ and

Xiang Zhao

^1,2

¹

School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China

²

Key Laboratory for Anisotropy and Texture of Materials, Northeastern University, Shenyang 110819, China

³

Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo 315201, China

^*

Author to whom correspondence should be addressed.

Materials 2020, 13(20), 4582; https://doi.org/10.3390/ma13204582

Submission received: 16 September 2020 / Revised: 7 October 2020 / Accepted: 12 October 2020 / Published: 14 October 2020

(This article belongs to the Section Advanced Materials Characterization)

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Abstract

This study investigates the effects of axial ultrasonic vibration on the microstructure evolution, residual stresses distribution and fatigue fracture behaviour of a 7N01-T4 joint, and demonstrates that ultrasonic vibration can significantly promote the flow of plasticised metals, expand the stirred zone (SZ) width and refine the grain size. The longitudinal residual stresses of the joints are dominant, and the peak longitudinal residual stresses of the thermo-mechanically affected zone (TMAZ) on the advancing side (AS) (TMAZ-AS) in the ultrasonic-assisted friction stir welding (UAFSW) joint are 31.5 MPa lower than those in the friction stir welding (FSW) joint. Compared to that of FSW joints, the fatigue strength of UAFSW joints increases by 20 MPa at 10⁷ cycles (stress ratio of R = 0.1). At high-stress levels, crack initiation occurs at the TMAZ-AS, and is mainly attributed to high residual stresses and second-phase particles. At low-stress levels, fatigue cracks are likely to initiate in the transition zone (TZ).

Keywords: ultrasonic-assisted friction stir welding; aluminium alloy; fatigue behaviour; microstructure; residual stresses

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MDPI and ACS Style

Zhang, Z.; He, C.; Li, Y.; Wei, J.; Zhai, M.; Zhao, S.; Zhao, X. Fatigue Behaviour of 7N01-T4 Aluminium Alloy Welded by Ultrasonic-Assisted Friction Stir Welding. Materials 2020, 13, 4582. https://doi.org/10.3390/ma13204582

AMA Style

Zhang Z, He C, Li Y, Wei J, Zhai M, Zhao S, Zhao X. Fatigue Behaviour of 7N01-T4 Aluminium Alloy Welded by Ultrasonic-Assisted Friction Stir Welding. Materials. 2020; 13(20):4582. https://doi.org/10.3390/ma13204582

Chicago/Turabian Style

Zhang, Zhiqiang, Changshu He, Ying Li, Jingxun Wei, Menggang Zhai, Su Zhao, and Xiang Zhao. 2020. "Fatigue Behaviour of 7N01-T4 Aluminium Alloy Welded by Ultrasonic-Assisted Friction Stir Welding" Materials 13, no. 20: 4582. https://doi.org/10.3390/ma13204582

APA Style

Zhang, Z., He, C., Li, Y., Wei, J., Zhai, M., Zhao, S., & Zhao, X. (2020). Fatigue Behaviour of 7N01-T4 Aluminium Alloy Welded by Ultrasonic-Assisted Friction Stir Welding. Materials, 13(20), 4582. https://doi.org/10.3390/ma13204582

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Fatigue Behaviour of 7N01-T4 Aluminium Alloy Welded by Ultrasonic-Assisted Friction Stir Welding

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