Effect of tool rotation rate on constituent particles in a friction stir processed 2024Al alloy

• Understanding of the effect of FSP tool rotation rate on constituent particles.
• A wide range of tool rotation rates studied (200–1000 rpm).
• Constituent particle microstructure in wrought 2024Al studied by SEM/EDS and DSC.
• May extend the understanding to other commercial alloy systems.

Friction stir processing (FSP) carried out on a commercial AA2024Al alloy using different tool rotation rates (200–1000 rpm) led to significant change in size and morphology of the constituent particles. The size of insoluble Al6(Cu,Mn,Fe) particles presentin the stir zone was substantially reduced as a function of tool rotation rate whereas smaller soluble Al–Cu–Mg based particles exhibited significant reduction in amount only at higher tool rotation rates. Severe plastic deformation, peak temperature and constituent particle characteristics influenced their evolution.