Understanding the Impact of Friction Stir Welding Parameters on Precipitation Processes in Aluminium Alloys

Aluminium alloys are traditionally strengthened by nanometer-sized precipitates. Friction stir

welding (FSW) is solid state joining process that is found suitable to join aluminium alloys as

it overcomes the issues associated with fusion welding of such alloys.

This project investigates

the impact of FSW parameters on precipitation processes in aluminium alloys, focusing on the

interplay between extreme thermomechanical conditions encountered during FSW and

microstructural evolution. The research will explore mechanisms such as continuous and

discontinuous recrystallisation, heterogeneous precipitation of second-phase particles, and the

transition between metastable and stable phases.

Emphasis will be placed on understanding

how variations in welding parameters influence grain structure, precipitation behavior, and

final mechanical properties. A major focus of the work will be on understanding the evolution

of the microstructure and precipitates employing advanced characterization tools such as high

resolution transmission electron microscopy (HRTEM) and atom probe tomography (APT) and

small-angle scattering.