THE EFFECT OF FRICTION STIR PROCESSING ON MICROTRUCTURE AND MECHINAL PROPERTIES OFAL 5052 ALLOY JOINT MADE BY TIG WELDING
Friction stir processing (FSP) is a solid-state amendment method to process the surface of metals. In this process, due to rotation and translation of a non- consumer tool, metal surface microstructure is refined and its mechanical characteristics are improved. Different methods were applied to improve the efficiency of FSP. In this research, Two pieces of aluminum were welded by TIC arc welding, a new method entitled friction stir vibration processing (FSVP) was presented to enhance the efficiency of FSP. The metal workpiece was vibrated normal to processing line during FSP. Microstructure and mechanical properties of Al5052 alloy specimens processed using FSP and FSVP methods were analyzed. The results showed that grain size decreased as vibration was used. It was also observed that yield and ultimate tensile strengths, in addition to hardness, increased as FSVP was applied. This was related to the enhanced straining of metal surface material as vibration was used. The increase in straining results in the increase of dislocation density which leads to more development of high angle grain boundaries due to dynamic recrystallization. The results also showed that strength and ductility of FSV processed specimens increased as vibration frequency increased. This new method is advised for application in industry.