Material Defects in Friction Stir Welding through Thermo-Mechanical Simulation: Dissimilar Materials with Tool Wear...

Area of Science:

• Materials Science and Engineering
• Computational Mechanics
• Manufacturing Processes

Background:

• Friction stir welding (FSW) is effective for dissimilar materials, but numerical simulation is limited.
• Predicting material mixing and defects in dissimilar FSW via simulation requires further study.
• The impact of tool wear on FSW simulations is often overlooked.

Purpose of the Study:

• To numerically investigate friction stir welding (FSW) of dissimilar materials.
• To develop a model for predicting material mixing and weld defects.
• To incorporate the effects of progressive tool wear into FSW simulations.

Main Methods:

• A coupled Eulerian-Lagrangian approach was used for numerical simulation.
• Material mixing and defects (tunnel, exit hole, flash) were simulated.
• Experimental validation was performed using AA6061 and AZ31B, with tool wear incorporated.

Main Results:

• The model successfully predicted subsurface tunnels, surface tunnels, flash formation, and exit holes with <1.2 mm deviation.
• Plate positioning significantly influenced defect formation, with AZ31B on the advancing side causing ~50% thicker surface tunnels.
• Tool wear, reducing pin length by up to 30%, was shown to cause surface tunnel defects.

Conclusions:

• The developed numerical model accurately predicts defects in dissimilar FSW.
• Tool wear significantly impacts defect formation and must be considered in simulations.
• This research advances the simulation capabilities for dissimilar material friction stir welding.