Heat and Material Flow Effects on Microstructures and Hardness in Friction-Stir Welded Joints

The experimental work carried out to study the heat and material flow effects on average grain size and hardness variation in Friction-stir welded joint of AA5052-H32 is presented. In order to quantify the heat input effects on the resulting microstructures and hardness, temperatures are measured at selected locations within the workpieces. Further, the thermo-mechanical effects due to tool's rotation are studied by examining the grain size variation across the weld geometry for different weld traverse speeds. Finally, the peak temperatures and average grain sizes are correlated qualitatively to the resulting hardness of the friction-stir welded joint.