• Hemant Deore
• Vijay Hiwarkar

Friction stir welding (FSW) is a solid state welding technology specially used for joining similar and dissimilar non-ferrous alloys like aluminium & magnesium alloys. FSW have numerous advantages over conventional welding methods like environment friendliness, energy efficiency, low distortion of material, lower loss of alloying elements, high strength of joint and versatility. In the current research, FSW of AA 6061 and AA5052 was carried out using two different tool geometries and by varying process parameters like tool rotational speed and traverse speed to establish its influence on the microstructure variation and mechanical properties of the welded joints. Metallographic observations of joints were carried out using optical and scanning electron microscopy. Hardness profile and residual stress were investigated. The welded joints were tested for tensile properties and impact toughness. It was confirmed that tool geometry and process parameters plays an important role in formation of defect free weld joint. Optical and scanning electron microscopy revealed that the elongated pancake microstructure of the base material (BM) was altered into a dynamically recrystallized microstructure of submicron grain size in the weld nugget. Strengthening precipitates, present in AA6061- T6 before welding, were found to be dissolved completely in the nugget zone (NZ), whereas overageing with much larger precipitates were observed in heat-affected zone (HAZ). Results of microhardness and tensile tests confirmed that the HAZ is the weakest region of the weld. The welded sheet exhibited reduced strength and ductility as compared to the BM. Impact energy of weld was lower than parent material. Compressive residual stresses were noticed in the weld nugget.

"Effect of tool Geometry and process parameters on microstructure and mechanical properties of Dissimilar Friction stir welding of AA6061-AA5052", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 4, page no.614-621, April-2019, Available :http://www.jetir.org/papers/JETIRBB06121.pdf

"Effect of tool Geometry and process parameters on microstructure and mechanical properties of Dissimilar Friction stir welding of AA6061-AA5052", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 4, page no. pp614-621, April-2019, Available at : http://www.jetir.org/papers/JETIRBB06121.pdf