Numerical and experimental investigation on AZ91 friction stir welding joints: mechanics, properties

Abstract

The present endeavour is to evaluate numerically and experimentally the influence of friction stir welding (FSW) parameters on peak temperatures, microstructures and mechanical properties of AZ91 magnesium alloy joints. A full 3D finite element ABAQUS model was developed to simulate the temperature distribution along the joint line. Therefrom, a total of nine different parametric combinations were derived for experimentations. Important insights relating to the material flow patterns and grain morphologies observed while altering the processing parameters have been elaborated. The parametric influence on the peak temperatures, grain morphologies, intermittent phases, tensile strength, and hardness are discussed through several mechanisms. Remarkably, the specimens prepared with the highest tool rotation speeds exhibited superior properties owing to several strengthening mechanisms.

KEYWORDS:

• Friction stir welding
• AZ91
• magnesium alloy
• numerical simulations
• tool rotation
• grain refinement
• intermetallic

Acknowledgements

The authors express their gratitude to the Mechanical workshop and welding research laboratory of Pandit Deendayal Energy University, Gandhinagar, India, for providing resources and support for completing this research work. Further gratitude to the Indian Space Research Organization, Government of India (in collaboration with Space Application Centre, Ahmedabad), for providing financial assistance for a project under RESPOND program (Project number – ISRO/RES/4/567/09-10). Under this project, a fully automatic three-axis vertical milling machine had been funded and used for experiments conducted.

We hereby declare that all authors contributed to the study's conception and design. The experimentation, material preparation, data collection, and analysis were performed by Ashish Desai, Vivek Patel, and Vishvesh Badheka. The first draft of the manuscript was written by Ashish Desai. Harikrishna Rana contributed to extra characterisation and manuscript revision. Bharat Khatri reviewed previous versions of the manuscript and provided valued suggestions. All authors read and approved the final manuscript.

We confirm that the manuscript has been approved by all authors for publication. I would like to declare on behalf of all co-authors that the work described herein is original research that has not been published previously.

Disclosure statement

No potential conflict of interest was reported by the author(s).