Application of Acoustic Emission as an Effective Tool to Monitor FSW of AA2024-T3 Aluminum Alloy

Abstract

Friction Stir Welding (FSW) is a solid-state welding technique used for joining metals and alloys to avoid problems associated with fusion welding. Acoustic Emission (AE) has been successfully used to monitor processes like metal cutting, grinding, electron beam welding and FSW. In this work, an attempt has been made to study the application of AE to monitor FSWs to produce defect free welds. During welding of aluminum alloy AA 2024-T3 5mm thick plates, AE signals were acquired. Patterns of AE signals produced during welding are helpful in identifying the defects produced. The lower and higher values of AE parameters help to decide the quality of welded joints. In order to have a better understanding of the behavior of AE parameters when defects were supposed to have occurred during welding, a time domain analysis of AE signals was carried out. The time domain analysis has resulted in justifying the behavior of the AE signals at the instant of occurrence of defects. The range of values of AE parameters, derived from AE signals found to be helpful in monitoring FSW, was accomplished by identifying the time of occurrence of the defect during welding followed by suitable corrective action to produce defect free welds.