Mechanical and Microstructural Investigation on Friction Stir Welded Aluminium – Steel Dissimilar Joints

aims: In this work an attempt was made to join aluminium alloy with the steel utilizing the friction stir welding process. During FSW, the tool travels through the propagation and dispersion of heat input per unit distance. background: Therefore, the quantity of heat input per unit of weld length is influenced by traversal speed. Heat is created because the tool spends less time spinning at extremely fast traversal speeds. objective: The materials are incorrectly mixed and compacted as a result, which reduces their strength. When the tool was moving rapidly, it generated enough heat at the right temperature to encourage grain growth and strain relief, increasing the impact strength of the joint. method: Micro-hardness varies over a distance in different zones depends on the grain size and phases underneath each depression. Micro-hardness often rises as a result of grain refining brought on by tool rotation in the SZ and TMAZ. result: But as the indentation distance from the SZ grows, the micro-hardness declines, especially in the HAZ and the BM's grain-coarsened region. conclusion: The distribution of micro-hardness also shows that dynamic recrystallization in the FSW leads to considerable grain refinement in the SZ. SZ is hence harder on the microscale than BM and HAZ. other: The various mechanisms such as climb, cross-slip and annihilation, causes rearrangement of dislocations and results in the formation of low angle grain boundaries and development of sub-grains were observed in micrograph.