Shear localisation modelling of friction stir weld formation process

Abstract

This paper presents a shear localisation model for studying friction stir welding (FSW) formation process. With this model, shear band (SB) width, SB formation time, and SB propagation speed can be theoretically estimated. The SB propagation speed in this context serves as a theoretical estimate of the maximum welding speed possible for a given material and prescribed welding conditions, such as stir pin rotation speed and torque level. The model is shown to provide reasonable estimates of shear localisation parameters against a set of recent experimental data on FSW of titanium alloy Ti–6Al–4V. With this model, titanium alloy Ti–6Al–4V, high strength low-alloy steel 4340, and aluminium alloy 2024 are compared in terms of shear localisation parameters, such as maximum SB propagation speeds (or welding speeds).

Keywords:

• Friction stir welding
• Deformation localisation
• Banded structure
• Rotational speed
• Translational speed

Acknowledgements

The authors acknowledge the support of this work in part by ONR Grant No. N00014-10-1-0479 at UNO and the National Research Foundation of Korea (NRF) Gant funded by the Korea government (MEST) through GCRC-SOP at University of Michigan under Project 2-1: Reliability and Strength Assessment of Core Parts and Material System.